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Positive-definite kernel

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and histograms: Histograms are frequently encountered in applications of real-life problems. Most observations are usually available under the form of nonnegative vectors of counts, which, if normalized, yield histograms of frequencies. It has been shown that the following family of squared metrics,
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including repetitions. Where sampling points lie dense, the true density function must take large values. A simple density estimate is possible by counting the number of samples in each cell of a grid, and plotting the resulting histogram, which yields a piecewise constant density estimate. A better
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which states that every minimizer function in an RKHS can be written as a linear combination of the kernel function evaluated at the training points. This is a practically useful result as it effectively simplifies the empirical risk minimization problem from an infinite dimensional to a finite
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Applications of p.d. kernels in various other branches of mathematics are in multivariate integration, multivariate optimization, and in numerical analysis and scientific computing, where one studies fast, accurate and adaptive algorithms ideally implemented in high-performance computing
4779:. The original object of Mercer’s paper was to characterize the kernels which are definite in the sense of Hilbert, but Mercer soon found that the class of such functions was too restrictive to characterize in terms of determinants. He therefore defined a continuous real symmetric kernel 4459: 3139: 5363:
Positive-definite kernels provide a framework that encompasses some basic Hilbert space constructions. In the following we present a tight relationship between positive-definite kernels and two mathematical objects, namely reproducing Hilbert spaces and feature maps.
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Positive-definite kernels, as defined in (1.1), appeared first in 1909 in a paper on integral equations by James Mercer. Several other authors made use of this concept in the following two decades, but none of them explicitly used kernels
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As stated earlier, positive definite kernels can be constructed from inner products. This fact can be used to connect p.d. kernels with another interesting object that arises in machine learning applications, namely the feature map. Let
1873: 6413:, by the reproducing property. This suggests a new look at p.d. kernels as inner products in appropriate Hilbert spaces, or in other words p.d. kernels can be viewed as similarity maps which quantify effectively how similar two points 4707: 9097:
Krein. M (1949/1950). "Hermitian-positive kernels on homogeneous spaces I and II" (in Russian), Ukrain. Mat. Z. 1(1949), pp. 64–98, and 2(1950), pp. 10–59. English translation: Amer. Math. Soc. Translations Ser. 2, 34 (1963), pp.
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Mercer, J. (1909). “Functions of positive and negative type and their connection with the theory of integral equations”. Philosophical Transactions of the Royal Society of London, Series A 209, pp. 415–446.
5498: 3134: 2076: 1981: 822: 7722: 1206: 8762: 2123: 768: 404: 6619: 7204: 3473: 1326: 5780: 8658: 1272: 1154: 588: 6180: 5325: 7941: 1437: 7316: 5720: 5327:. This property is called the reproducing property of the kernel and turns out to have importance in the solution of boundary-value problems for elliptic partial differential equations. 2782: 1377: 712: 523:, and positive semi-definite (p.s.d.) kernels, which do not impose this condition. Note that this is equivalent to requiring that every finite matrix constructed by pairwise evaluation, 9070:
Young, W. H. (1909). "A note on a class of symmetric functions and on a theorem required in the theory of integral equations", Philos. Trans. Roy.Soc. London, Ser. A, 209, pp. 415–446.
6872: 3406:{\displaystyle \sum _{i,j=1}^{n}c_{i}c_{j}(x_{i},x_{j})_{H}=\left(\sum _{i=1}^{n}c_{i}x_{i},\sum _{j=1}^{n}c_{j}x_{j}\right)_{H}=\left\|\sum _{i=1}^{n}c_{i}x_{i}\right\|_{H}^{2}\geq 0} 5585: 3942:{\displaystyle \psi _{H_{1}}=\sum _{i}\left|{\sqrt {\theta _{i}}}-{\sqrt {\theta _{i}'}}\right|,\psi _{H_{2}}=\sum _{i}\left|{\sqrt {\theta _{i}}}-{\sqrt {\theta _{i}'}}\right|^{2},} 5642: 1554: 986: 8159: 1716: 3447: 521: 7258: 6047: 5439: 7396: 4588: 7450: 5006:
At about the same time W. H. Young, motivated by a different question in the theory of integral equations, showed that for continuous kernels condition (1.1) is equivalent to
2115: 1004: 3765:{\displaystyle \psi _{\chi ^{2}}=\sum _{i}{\frac {(\theta _{i}-\theta _{i}')^{2}}{\theta _{i}+\theta _{i}'}},\quad \psi _{TV}=\sum _{i}\left|\theta _{i}-\theta _{i}'\right|,} 8706: 7854: 7340: 6954: 6791: 6268: 5836: 4901:, and he proved that (1.1) is a necessary and sufficient condition for a kernel to be of positive type. Mercer then proved that for any continuous p.d. kernel the expansion 4127: 1442: 210: 135: 7523: 4548: 4109: 2494:{\displaystyle K(\mathbf {x} ,\mathbf {y} )=e^{-{\frac {\|\mathbf {x} -\mathbf {y} \|^{2}}{2\sigma ^{2}}}},\quad \mathbf {x} ,\mathbf {y} \in \mathbb {R} ^{d},\sigma >0} 8451: 6663: 6202:
follows from the p.d. property of the inner product. On the other hand, every p.d. kernel, and its corresponding RKHS, have many associated feature maps. For example: Let
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Schaback, R. and Wendland, H. (2006). "Kernel Techniques: From Machine Learning to Meshless Methods", Cambridge University Press, Acta Numerica (2006), pp. 1–97.
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Berg, C., Christensen, J. P. R., and Ressel, P. (1984). "Harmonic Analysis on Semigroups". Number 100 in Graduate Texts in Mathematics, Springer Verlag.
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Every reproducing kernel is positive-definite, and every positive definite kernel defines a unique RKHS, of which it is the unique reproducing kernel.
2615:{\displaystyle K(\mathbf {x} ,\mathbf {y} )=e^{-\alpha \|\mathbf {x} -\mathbf {y} \|},\quad \mathbf {x} ,\mathbf {y} \in \mathbb {R} ^{d},\alpha >0} 7404:
On the other hand, n.d. kernels can be identified with a subfamily of p.d. kernels known as infinitely divisible kernels. A nonnegative-valued kernel
2628: 2344:{\displaystyle K(\mathbf {x} ,\mathbf {y} )=(\mathbf {x} ^{T}\mathbf {y} +r)^{n},\quad \mathbf {x} ,\mathbf {y} \in \mathbb {R} ^{d},r\geq 0,n\geq 1} 9061:
Hilbert, D. (1904). "Grundzuge einer allgemeinen Theorie der linearen Integralgleichungen I", Gott. Nachrichten, math.-phys. K1 (1904), pp. 49–91.
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In the literature on computer experiments and other engineering experiments, one increasingly encounters models based on p.d. kernels, RBFs or
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Positive-definite kernels, through their equivalence with reproducing kernel Hilbert spaces (RKHS), are particularly important in the field of
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One link between distances and p.d. kernels is given by a particular kind of kernel, called a negative definite kernel, and defined as follows
7342:. At the same time each distance does not correspond necessarily to a n.d. kernel. This is only true for Hilbertian distances, where distance 9024: 8986: 7082: 5343: 7622: 8955: 600: 143: 409: 8912: 6299: 6104: 5330:
Another line of development in which p.d. kernels played a large role was the theory of harmonics on homogeneous spaces as begun by
6488:. Moreover, through the equivalence of p.d. kernels and its corresponding RKHS, every feature map can be used to construct a RKHS. 5444: 3080: 8991: 5358: 2033: 8916: 4454:{\displaystyle \int _{a}^{b}\int _{a}^{b}K(s,t)x(s)x(t)\ \mathrm {d} s\,\mathrm {d} t=\sum {\frac {1}{\lambda _{n}}}\left^{2},} 1945: 773: 477:
In probability theory, a distinction is sometimes made between positive-definite kernels, for which equality in (1.1) implies
2204:{\displaystyle K(\mathbf {x} ,\mathbf {y} )=\mathbf {x} ^{T}\mathbf {y} ,\quad \mathbf {x} ,\mathbf {y} \in \mathbb {R} ^{d}} 992:. In the rest of this article we assume real-valued functions, which is the common practice in applications of p.d. kernels. 1159: 8420:
can be obtained by using kernel interpolation with the covariance kernel, ignoring the probabilistic background completely.
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Rosasco, L. and Poggio, T. (2015). "A Regularization Tour of Machine Learning – MIT 9.520 Lecture Notes" Manuscript.
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The parallel between n.d. kernels and distances is in the following: whenever a n.d. kernel vanishes on the set
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seem not to have been aware of the study of p.d. kernels). Mercer’s work arose from Hilbert’s paper of 1904 on
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In mathematical literature, kernels are usually complex-valued functions. That is, a complex-valued function
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Haaland, B. and Qian, P. Z. G. (2010). "Accurate emulators for large-scale computer experiments", Ann. Stat.
5590: 957: 8391:. Such a kernel exists and is positive-definite under weak additional assumptions. Now a good estimate for 8128: 3577:{\displaystyle \psi _{JD}=H\left({\frac {\theta +\theta '}{2}}\right)-{\frac {H(\theta )+H(\theta ')}{2}},} 3418: 480: 86: 6013: 5410: 1089:{\displaystyle (K_{i})_{i\in \mathbb {N} },\ \ K_{i}:{\mathcal {X}}\times {\mathcal {X}}\to \mathbb {R} } 9079:
Moore, E.H. (1916). "On properly positive Hermitian matrices", Bull. Amer. Math. Soc. 23, 59, pp. 66–67.
7365: 7209: 7427: 1544:{\displaystyle (K_{i})_{i=1}^{n},\ \ K_{i}:{\mathcal {X}}_{i}\times {\mathcal {X}}_{i}\to \mathbb {R} } 2091: 6564: 8687: 7835: 7321: 6935: 6737: 6231: 5787: 191: 116: 8971: 7747: 7482: 4520: 4058: 4049: 8427: 6627: 6052: 4557: 8981: 8920: 8907:. Some of the popular meshfree methods are closely related to positive-definite kernels (such as 8456: 7529: 3041:{\displaystyle K(x,y)=\operatorname {sinc} (\alpha (x-y)),\quad x,y\in \mathbb {R} ,\alpha >0} 138: 102: 66: 17: 6500:. In this section we discuss parallels between their two respective ingredients, namely kernels 5932:
Now the connection between positive definite kernels and RKHS is given by the following theorem
5176: 5044: 5009: 4817: 944:{\displaystyle \sum _{i=1}^{n}\sum _{j=1}^{n}\xi _{i}{\overline {\xi }}_{j}K(x_{i},x_{j})\geq 0} 5150: 4712: 1706:{\displaystyle K((x_{1},\dots ,x_{n}),(y_{1},\dots ,y_{n}))=\prod _{i=1}^{n}K_{i}(x_{i},y_{i})} 9020: 8976: 8958:. Here one often uses implicit surface models to approximate or interpolate point cloud data. 8951: 8320: 8027: 7535: 6668: 2916: 2214: 1868:{\displaystyle K((x_{1},\dots ,x_{n}),(y_{1},\dots ,y_{n}))=\sum _{i=1}^{n}K_{i}(x_{i},y_{i})} 989: 98: 82: 58: 7576: 6101:
the feature space. It is easy to see that every feature map defines a unique p.d. kernel by
5206:. Moore was interested in generalization of integral equations and showed that to each such 8900: 8894: 6456: 6273: 5867: 5841: 5523: 5115: 4782: 4747: 94: 74: 62: 9088:
Moore, E.H. (1935). "General Analysis, Part I", Memoirs Amer. Philos. Soc. 1, Philadelphia.
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is called a reproducing kernel Hilbert space if the evaluation functionals are continuous.
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and S. Ito. The most comprehensive theory of p.d. kernels in homogeneous spaces is that of
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In probability theory, p.d. kernels arise as covariance kernels of stochastic processes.
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of (1.2). Hilbert defined a “definite” kernel as one for which the double integral
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Every RKHS has a special function associated to it, namely the reproducing kernel:
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There are several different ways in which kernels arise in probability theory.
2721:{\displaystyle K(x,y)=e^{-\alpha |x-y|},\quad x,y\in \mathbb {R} ,\alpha >0} 9107:
Loève, M. (1960). "Probability theory", 2nd ed., Van Nostrand, Princeton, N.J.
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estimate can be obtained by using a nonnegative translation invariant kernel
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Nondeterministic recovery problems: Assume that we want to find the response
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The following result shows equivalence between RKHS and reproducing kernels:
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Fast radial basis function interpolation via preconditioned Krylov iteration
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will often show similar behaviour. This is described by a covariance kernel
327:{\displaystyle \sum _{i=1}^{n}\sum _{j=1}^{n}c_{i}c_{j}K(x_{i},x_{j})\geq 0} 7532:, where the first constraint on the distance function is loosened to allow 5342:
which includes as special cases the work on p.d. functions and irreducible
9043:". In Ghahramani, Z. and Cowell, R., editors, Proceedings of AISTATS 2005. 5092:
E.H. Moore initiated the study of a very general kind of p.d. kernel. If
7398: 6925:{\displaystyle \psi :{\mathcal {X}}\times {\mathcal {X}}\to \mathbb {R} } 9041:
Hilbertian metrics and positive definite kernels on probability measures
8943: 7318:, and is zero only on this set, then its square root is a distance for 7145:{\displaystyle n\in \mathbb {N} ,x_{1},\dots ,x_{n}\in {\mathcal {X}},} 5928:
induces a unique RKHS, and every RKHS has a unique reproducing kernel.
3470:-square, Total Variation, and two variations of the Hellinger distance: 6543:
Here by a distance function between each pair of elements of some set
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Density estimation by kernels: The problem is to recover the density
638:{\displaystyle K:{\mathcal {X}}\times {\mathcal {X}}\to \mathbb {C} } 181:{\displaystyle K:{\mathcal {X}}\times {\mathcal {X}}\to \mathbb {R} } 6496:
Kernel methods are often compared to distance based methods such as
467:{\displaystyle n\in \mathbb {N} ,c_{1},\dots ,c_{n}\in \mathbb {R} } 8560:
is identical to the above one, but with a modified kernel given by
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Connection with reproducing kernel Hilbert spaces and feature maps
8950:. Other types of applications that boil down to data fitting are 6406:{\displaystyle (\Phi (x),\Phi (y))_{F}=(K_{x},K_{y})_{H}=K(x,y)} 3949:
can be used to define p.d. kernels using the following formula
590:, has either entirely positive (p.d.) or nonnegative (p.s.d.) 9019:. Providence, RI: American Mathematical Soc. pp. 45–47. 5644:. We first define a reproducing kernel Hilbert space (RKHS): 5493:{\displaystyle (\cdot ,\cdot )_{H}:H\times H\to \mathbb {R} } 3129:{\displaystyle (\cdot ,\cdot )_{H}:H\times H\to \mathbb {R} } 137:
be a nonempty set, sometimes referred to as the index set. A
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Common examples of p.d. kernels defined on Euclidean space
2071:{\displaystyle {\mathcal {X}}_{0}\times {\mathcal {X}}_{0}} 8024:
but rather a realization of a real-valued random variable
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defined on that set, i.e. any nonnegative-valued function
30:"Kernel function" redirects here. Not to be confused with 7856:, provided that we have a sample of input-response pairs 5894:
The latter property is called the reproducing property.
1976:{\displaystyle {\mathcal {X}}_{0}\subset {\mathcal {X}}} 817:{\displaystyle \xi _{1},\dots ,\xi _{n}\in \mathbb {C} } 714:
and positive definite if for every finite set of points
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there, then the problem of finding a good estimate for
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is called Hilbertian if one can embed the metric space
7717:{\displaystyle d(x,y)={\sqrt {K(x,x)-2K(x,y)+K(y,y)}}} 7212: 1201:{\displaystyle \lambda _{1},\dots ,\lambda _{n}\geq 0} 9017:
Expansions in eigenfunctions of selfadjoint operators
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in the early 20th century, in the context of solving
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Numerical solution of partial differential equations
8757:{\displaystyle x_{1},\dots ,x_{n}\in {\mathcal {X}}} 8060:. The goal is to get information about the function 763:{\displaystyle x_{1},\dots ,x_{n}\in {\mathcal {X}}} 399:{\displaystyle x_{1},\dots ,x_{n}\in {\mathcal {X}}} 8899:One of the greatest application areas of so-called 8500:, such that the noise is independent for different 6614:{\displaystyle {\mathcal {X}}\times {\mathcal {X}}} 4814:to be of positive type (i.e. positive-definite) if 8876: 8777: 8756: 8700: 8676: 8652: 8552: 8532: 8512: 8492: 8472: 8445: 8412: 8383: 8309: 8280: 8251: 8231: 8211: 8182: 8153: 8117: 8097: 8052: 8016: 7989: 7962: 7935: 7848: 7824: 7804: 7784: 7716: 7611: 7591: 7565: 7517: 7471: 7444: 7416: 7390: 7354: 7334: 7310: 7252: 7199:{\displaystyle c_{1},\dots ,c_{n}\in \mathbb {R} } 7198: 7144: 7055: 6948: 6924: 6866: 6785: 6724: 6698: 6657: 6613: 6579: 6555: 6532: 6512: 6480: 6445: 6425: 6405: 6288: 6262: 6220: 6194: 6174: 6093: 6073: 6041: 6002: 5978: 5966:, it is possible to build an associated RKHS with 5958: 5920: 5882: 5856: 5830: 5774: 5714: 5663: 5636: 5579: 5538: 5512: 5492: 5433: 5399: 5379: 5319: 5238: 5218: 5198: 5165: 5139: 5104: 5081: 5033: 4995: 4893: 4861: 4841: 4806: 4771: 4736: 4701: 4573: 4542: 4509: 4489: 4453: 4225: 4103: 4032: 3941: 3764: 3576: 3462: 3441: 3405: 3128: 3065: 3040: 2932: 2905: 2776: 2720: 2614: 2493: 2343: 2203: 2109: 2070: 2022: 2002: 1975: 1931: 1867: 1705: 1543: 1431: 1371: 1321:{\displaystyle a_{1},\dots ,a_{n}\in \mathbb {N} } 1320: 1266: 1200: 1148: 1088: 980: 943: 816: 762: 706: 637: 582: 515: 466: 398: 326: 204: 180: 129: 9156:". SIAM J. Scient. Computing 29/5, pp. 1876–1899. 7943:given by observation or experiment. The response 5775:{\displaystyle K_{x}(\cdot )\in H,\forall x\in X} 8653:{\displaystyle K(x,y)=E+\sigma ^{2}\delta _{xy}} 7424:is said to be infinitely divisible if for every 1344: 1267:{\displaystyle K_{1}^{a_{1}}\dots K_{n}^{a_{n}}} 1149:{\displaystyle \sum _{i=1}^{n}\lambda _{i}K_{i}} 583:{\displaystyle \mathbf {K} _{ij}=K(x_{i},x_{j})} 8785:, with total integral equal to one, and define 8125:in the deterministic setting. For two elements 6932:is called a negative definite (n.d.) kernel on 6175:{\displaystyle K(x,y)=(\Phi (x),\Phi (y))_{F}.} 5320:{\displaystyle f\in H,f(y)=(f,K(\cdot ,y))_{H}} 188:is called a positive-definite (p.d.) kernel on 7936:{\displaystyle (x_{i},f_{i})=(x_{i},f(x_{i}))} 6081:is called a feature map. In this case we call 1432:{\displaystyle ({\mathcal {X}}_{i})_{i=1}^{n}} 8919:). These methods use radial basis kernel for 8684:of a multivariate distribution over a domain 7528:Another link is that a p.d. kernel induces a 7311:{\displaystyle \{(x,x):x\in {\mathcal {X}}\}} 4111:, i.e. p.d. functions (indeed M. Mathias and 8: 7305: 7271: 4537: 4524: 2891: 2878: 2825: 2812: 2563: 2547: 2418: 2401: 27:Generalization of a positive-definite matrix 9152:Gumerov, N. A. and Duraiswami, R. (2007). " 5936: 5902: 5715:{\displaystyle K:X\times X\to \mathbb {R} } 2777:{\displaystyle W_{2}^{k}(\mathbb {R} ^{d})} 1372:{\displaystyle K=\lim _{n\to \infty }K_{n}} 707:{\displaystyle K(x,y)={\overline {K(y,x)}}} 4690: 500: 8913:Reproducing kernel particle method (RKPM) 8858: 8845: 8832: 8821: 8807: 8790: 8770: 8748: 8747: 8738: 8719: 8713: 8692: 8691: 8689: 8669: 8641: 8631: 8565: 8545: 8525: 8505: 8485: 8464: 8458: 8429: 8396: 8322: 8293: 8264: 8244: 8224: 8195: 8166: 8145: 8144: 8130: 8110: 8083: 8065: 8041: 8029: 8008: 8002: 7981: 7975: 7954: 7948: 7921: 7902: 7883: 7870: 7861: 7840: 7839: 7837: 7817: 7797: 7768: 7647: 7624: 7604: 7578: 7537: 7509: 7499: 7484: 7463: 7457: 7438: 7437: 7429: 7409: 7373: 7372: 7367: 7347: 7326: 7325: 7323: 7299: 7298: 7269: 7238: 7228: 7217: 7211: 7192: 7191: 7182: 7163: 7157: 7133: 7132: 7123: 7104: 7093: 7092: 7084: 7038: 7025: 7009: 6999: 6989: 6972: 6966: 6940: 6939: 6937: 6918: 6917: 6908: 6907: 6898: 6897: 6889: 6867:{\displaystyle d(x,z)\leq d(x,y)+d(y,z).} 6799: 6739: 6711: 6670: 6629: 6605: 6604: 6595: 6594: 6592: 6572: 6548: 6525: 6505: 6458: 6438: 6418: 6376: 6366: 6353: 6337: 6301: 6275: 6254: 6233: 6207: 6187: 6163: 6106: 6086: 6054: 6049:the corresponding inner product. Any map 6033: 6015: 5995: 5971: 5951: 5913: 5869: 5843: 5804: 5789: 5736: 5730: 5708: 5707: 5687: 5656: 5604: 5592: 5573: 5572: 5557: 5551: 5525: 5505: 5486: 5485: 5464: 5446: 5427: 5426: 5412: 5392: 5372: 5311: 5251: 5231: 5211: 5184: 5178: 5152: 5117: 5097: 5058: 5046: 5011: 4985: 4965: 4946: 4939: 4933: 4906: 4874: 4854: 4819: 4784: 4749: 4714: 4691: 4682: 4631: 4626: 4616: 4611: 4590: 4565: 4559: 4531: 4522: 4502: 4482: 4442: 4429: 4428: 4401: 4391: 4386: 4368: 4359: 4345: 4344: 4336: 4285: 4280: 4270: 4265: 4259: 4212: 4173: 4168: 4129: 4060: 3986: 3954: 3930: 3914: 3908: 3897: 3891: 3879: 3864: 3859: 3836: 3830: 3819: 3813: 3802: 3787: 3782: 3776: 3745: 3732: 3717: 3701: 3681: 3668: 3656: 3643: 3630: 3620: 3614: 3599: 3594: 3588: 3530: 3500: 3481: 3475: 3455: 3433: 3428: 3424: 3423: 3420: 3391: 3386: 3375: 3365: 3355: 3344: 3325: 3314: 3304: 3294: 3283: 3270: 3260: 3250: 3239: 3220: 3210: 3197: 3184: 3174: 3164: 3147: 3141: 3122: 3121: 3100: 3082: 3058: 3022: 3021: 2952: 2924: 2918: 2894: 2863: 2856: 2840: 2833: 2828: 2789: 2765: 2761: 2760: 2750: 2745: 2739: 2702: 2701: 2678: 2664: 2657: 2630: 2594: 2590: 2589: 2580: 2572: 2558: 2550: 2540: 2525: 2517: 2509: 2473: 2469: 2468: 2459: 2451: 2436: 2421: 2412: 2404: 2398: 2394: 2379: 2371: 2363: 2311: 2307: 2306: 2297: 2289: 2279: 2264: 2258: 2253: 2238: 2230: 2222: 2195: 2191: 2190: 2181: 2173: 2164: 2158: 2153: 2141: 2133: 2125: 2101: 2097: 2096: 2093: 2062: 2056: 2055: 2045: 2039: 2038: 2035: 2015: 1994: 1988: 1967: 1966: 1957: 1951: 1950: 1947: 1923: 1917: 1916: 1900: 1894: 1893: 1883: 1882: 1880: 1856: 1843: 1830: 1820: 1809: 1790: 1771: 1752: 1733: 1718: 1694: 1681: 1668: 1658: 1647: 1628: 1609: 1590: 1571: 1556: 1537: 1536: 1527: 1521: 1520: 1510: 1504: 1503: 1493: 1474: 1463: 1453: 1444: 1423: 1412: 1402: 1396: 1395: 1389: 1363: 1347: 1335: 1314: 1313: 1304: 1285: 1279: 1256: 1251: 1246: 1231: 1226: 1221: 1215: 1186: 1167: 1161: 1140: 1130: 1120: 1109: 1103: 1082: 1081: 1072: 1071: 1062: 1061: 1052: 1033: 1032: 1025: 1015: 1006: 972: 962: 959: 926: 913: 897: 887: 880: 870: 859: 849: 838: 832: 810: 809: 800: 781: 775: 754: 753: 744: 725: 719: 677: 654: 631: 630: 621: 620: 611: 610: 602: 571: 558: 536: 531: 528: 488: 482: 460: 459: 450: 431: 420: 419: 411: 390: 389: 380: 361: 355: 309: 296: 280: 270: 260: 249: 239: 228: 222: 196: 195: 193: 174: 173: 164: 163: 154: 153: 145: 121: 120: 118: 7619:, we can define a distance function as: 7452:there exists a positive-definite kernel 9007: 5946:Thus, given a positive-definite kernel 5580:{\displaystyle e_{x}:H\to \mathbb {R} } 5112:is an abstract set, he calls functions 4497:is a continuous real symmetric kernel, 3077:, then its corresponding inner product 5637:{\displaystyle f\mapsto e_{x}(f)=f(x)} 4249:In particular, Hilbert had shown that 2947:Kernel generating Paley–Wiener space: 1551:a sequence of p.d. kernels, then both 981:{\displaystyle {\overline {\xi }}_{j}} 9015:Berezanskij, Jurij MakaroviÄŤ (1968). 8987:Positive-definite function on a group 8917:smoothed-particle hydrodynamics (SPH) 8909:meshless local Petrov Galerkin (MLPG) 8219:will not be uncorrelated, because if 8154:{\displaystyle x,y\in {\mathcal {X}}} 7: 8259:the random experiments described by 6958: 4251: 4121: 3450:respectively Jensen divergence, the 3442:{\displaystyle \mathbb {R} _{+}^{d}} 516:{\displaystyle c_{i}=0\;(\forall i)} 214: 9039:Hein, M. and Bousquet, O. (2005). " 7599:. Given a positive-definite kernel 7253:{\textstyle \sum _{i=1}^{n}c_{i}=0} 6042:{\displaystyle (\cdot ,\cdot )_{F}} 5682:: Reproducing kernel is a function 5500:the corresponding inner product on 5434:{\displaystyle f:X\to \mathbb {R} } 7751:dimensional optimization problem. 7391:{\displaystyle ({\mathcal {X}},d)} 6321: 6306: 6235: 6147: 6132: 6056: 5760: 4849:for all real continuous functions 4692: 4683: 4430: 4346: 4337: 4213: 3136:is a p.d. kernel. Indeed, we have 1354: 504: 25: 8424:Assume now that a noise variable 7445:{\displaystyle n\in \mathbb {N} } 6182:Indeed, positive definiteness of 5246:of functions such that, for each 2942:Bessel function of the third kind 18:Positive-definite kernel function 8992:Reproducing kernel Hilbert space 8903:is in the numerical solution of 5359:Reproducing kernel Hilbert space 5003:holds absolutely and uniformly. 2581: 2573: 2559: 2551: 2526: 2518: 2460: 2452: 2413: 2405: 2380: 2372: 2298: 2290: 2265: 2254: 2239: 2231: 2182: 2174: 2165: 2154: 2142: 2134: 2110:{\displaystyle \mathbb {R} ^{d}} 532: 7755:Kernels in probabilistic models 3696: 3008: 2688: 2571: 2450: 2288: 2172: 8801: 8795: 8701:{\displaystyle {\mathcal {X}}} 8621: 8618: 8612: 8603: 8597: 8591: 8582: 8570: 8453:, with zero mean and variance 8440: 8434: 8407: 8401: 8378: 8375: 8369: 8360: 8354: 8348: 8339: 8327: 8304: 8298: 8275: 8269: 8206: 8200: 8177: 8171: 8092: 8089: 8076: 8070: 8047: 8034: 7930: 7927: 7914: 7895: 7889: 7863: 7849:{\displaystyle {\mathcal {X}}} 7779: 7773: 7709: 7697: 7688: 7676: 7664: 7652: 7641: 7629: 7554: 7542: 7506: 7492: 7385: 7369: 7335:{\displaystyle {\mathcal {X}}} 7286: 7274: 7044: 7018: 6949:{\displaystyle {\mathcal {X}}} 6914: 6858: 6846: 6837: 6825: 6816: 6804: 6786:{\displaystyle d(x,y)=d(y,x),} 6777: 6765: 6756: 6744: 6687: 6675: 6646: 6634: 6475: 6463: 6400: 6388: 6373: 6346: 6334: 6330: 6324: 6315: 6309: 6303: 6263:{\displaystyle \Phi (x)=K_{x}} 6244: 6238: 6160: 6156: 6150: 6141: 6135: 6129: 6123: 6111: 6065: 6030: 6017: 5831:{\displaystyle (f,K_{x})=f(x)} 5825: 5819: 5810: 5791: 5748: 5742: 5704: 5631: 5625: 5616: 5610: 5597: 5569: 5482: 5461: 5448: 5423: 5308: 5304: 5292: 5280: 5274: 5268: 5134: 5122: 5076: 5064: 5022: 5016: 4977: 4971: 4958: 4952: 4923: 4911: 4888: 4876: 4830: 4824: 4801: 4789: 4760: 4754: 4725: 4719: 4676: 4670: 4664: 4658: 4652: 4640: 4601: 4595: 4425: 4419: 4413: 4407: 4330: 4324: 4318: 4312: 4306: 4294: 4206: 4200: 4194: 4182: 4155: 4149: 4140: 4134: 4098: 4086: 4077: 4065: 4013: 3996: 3976: 3959: 3653: 3623: 3562: 3551: 3542: 3536: 3382: 3336: 3217: 3190: 3118: 3097: 3084: 3002: 2999: 2987: 2981: 2969: 2957: 2900: 2875: 2806: 2794: 2771: 2756: 2679: 2665: 2647: 2635: 2530: 2514: 2384: 2368: 2276: 2249: 2243: 2227: 2146: 2130: 1862: 1836: 1799: 1796: 1764: 1758: 1726: 1723: 1700: 1674: 1637: 1634: 1602: 1596: 1564: 1561: 1533: 1460: 1446: 1409: 1391: 1351: 1078: 1022: 1008: 932: 906: 695: 683: 671: 659: 627: 577: 551: 510: 501: 315: 289: 205:{\displaystyle {\mathcal {X}}} 170: 130:{\displaystyle {\mathcal {X}}} 91:partial differential equations 1: 7792:of an unknown model function 7518:{\displaystyle K=(K_{n})^{n}} 5407:a Hilbert space of functions 4543:{\displaystyle \{\psi _{n}\}} 4104:{\displaystyle K(x,y)=f(x-y)} 1001:For a family of p.d. kernels 53:. It was first introduced by 41:, a branch of mathematics, a 8948:response surface methodology 8933:Stinespring dilation theorem 8927:Stinespring dilation theorem 8446:{\displaystyle \epsilon (x)} 6658:{\displaystyle d(x,y)\geq 0} 6074:{\displaystyle \Phi :X\to F} 4574:{\displaystyle \lambda _{n}} 1379:is p.d. if the limit exists. 967: 892: 699: 8473:{\displaystyle \sigma ^{2}} 7997:is not a fixed function of 7744:statistical learning theory 7732:Kernels in machine learning 5346:of locally compact groups. 4117:Fredholm integral equations 1439:is a sequence of sets, and 59:integral operator equations 9193: 8930: 8892: 7746:because of the celebrated 7735: 5546:the evaluation functional 5356: 5334:in 1929, and continued by 5199:{\displaystyle x_{i}\in E} 5082:{\displaystyle x\in L^{1}} 5034:{\displaystyle J(x)\geq 0} 4842:{\displaystyle J(x)\geq 0} 4552:orthonormal eigenfunctions 4047: 47:positive-definite function 29: 7401:into some Hilbert space. 5986:as a reproducing kernel. 5908:Every reproducing kernel 5226:there is a Hilbert space 5166:{\displaystyle E\times E} 4737:{\displaystyle J(x)>0} 4581:’s are the corresponding 45:is a generalization of a 8384:{\displaystyle K(x,y)=E} 8053:{\displaystyle Z(x_{i})} 7566:{\displaystyle d(x,y)=0} 6699:{\displaystyle d(x,y)=0} 6010:be a Hilbert space, and 4550:is a complete system of 2933:{\displaystyle B_{\nu }} 2083:Examples of p.d. kernels 770:and any complex numbers 51:positive-definite matrix 43:positive-definite kernel 7592:{\displaystyle x\neq y} 6884:: A symmetric function 5344:unitary representations 1983:. Then the restriction 996:Some general properties 87:boundary-value problems 75:complex function-theory 8878: 8837: 8779: 8758: 8708:, from a large sample 8702: 8678: 8654: 8554: 8534: 8514: 8494: 8474: 8447: 8414: 8385: 8311: 8282: 8253: 8233: 8213: 8184: 8155: 8119: 8099: 8054: 8018: 7991: 7964: 7937: 7850: 7826: 7806: 7786: 7718: 7613: 7593: 7567: 7519: 7473: 7446: 7418: 7392: 7356: 7336: 7312: 7262: 7254: 7233: 7200: 7146: 7057: 6994: 6950: 6926: 6868: 6787: 6726: 6700: 6659: 6615: 6581: 6557: 6534: 6514: 6482: 6481:{\displaystyle K(x,y)} 6453:are through the value 6447: 6427: 6407: 6290: 6289:{\displaystyle x\in X} 6264: 6222: 6196: 6176: 6095: 6075: 6043: 6004: 5980: 5960: 5922: 5896: 5884: 5883:{\displaystyle x\in X} 5858: 5857:{\displaystyle f\in H} 5832: 5776: 5716: 5673: 5665: 5638: 5581: 5540: 5539:{\displaystyle x\in X} 5514: 5494: 5435: 5401: 5381: 5321: 5240: 5220: 5200: 5167: 5141: 5140:{\displaystyle K(x,y)} 5106: 5083: 5035: 4997: 4895: 4863: 4843: 4808: 4807:{\displaystyle K(s,t)} 4773: 4772:{\displaystyle x(t)=0} 4738: 4703: 4575: 4544: 4511: 4491: 4455: 4227: 4105: 4034: 3943: 3766: 3578: 3464: 3443: 3407: 3360: 3299: 3255: 3169: 3130: 3067: 3042: 2934: 2907: 2778: 2722: 2616: 2495: 2345: 2205: 2111: 2078:is also a p.d. kernel. 2072: 2024: 2004: 1977: 1933: 1869: 1825: 1707: 1663: 1545: 1433: 1373: 1322: 1268: 1202: 1150: 1125: 1090: 982: 945: 875: 854: 818: 764: 708: 639: 584: 517: 468: 400: 328: 265: 244: 206: 182: 131: 8931:Further information: 8893:Further information: 8884:as a smooth estimate. 8879: 8817: 8780: 8759: 8703: 8679: 8655: 8555: 8535: 8515: 8495: 8475: 8448: 8415: 8386: 8312: 8283: 8254: 8234: 8214: 8185: 8161:the random variables 8156: 8120: 8100: 8055: 8019: 8017:{\displaystyle x_{i}} 7992: 7990:{\displaystyle x_{i}} 7965: 7963:{\displaystyle f_{i}} 7938: 7851: 7827: 7807: 7787: 7736:Further information: 7719: 7614: 7594: 7568: 7520: 7474: 7472:{\displaystyle K_{n}} 7447: 7419: 7393: 7357: 7337: 7313: 7255: 7213: 7201: 7147: 7058: 6968: 6951: 6927: 6879: 6869: 6788: 6727: 6701: 6660: 6616: 6582: 6558: 6535: 6515: 6492:Kernels and distances 6483: 6448: 6428: 6408: 6291: 6265: 6223: 6197: 6177: 6096: 6076: 6044: 6005: 5981: 5961: 5923: 5885: 5859: 5833: 5777: 5717: 5677: 5666: 5646: 5639: 5582: 5541: 5515: 5495: 5436: 5402: 5382: 5357:Further information: 5322: 5241: 5221: 5201: 5168: 5142: 5107: 5084: 5036: 4998: 4896: 4864: 4844: 4809: 4774: 4739: 4704: 4576: 4545: 4512: 4492: 4456: 4228: 4106: 4035: 3944: 3767: 3579: 3465: 3463:{\displaystyle \chi } 3444: 3408: 3340: 3279: 3235: 3143: 3131: 3068: 3043: 2935: 2908: 2779: 2723: 2617: 2496: 2346: 2206: 2112: 2073: 2025: 2005: 2003:{\displaystyle K_{0}} 1978: 1934: 1870: 1805: 1708: 1643: 1546: 1434: 1374: 1323: 1269: 1203: 1151: 1105: 1091: 983: 946: 855: 834: 819: 765: 709: 640: 585: 518: 469: 401: 329: 245: 224: 207: 183: 132: 8946:. One such topic is 8789: 8769: 8712: 8688: 8668: 8564: 8544: 8524: 8504: 8484: 8457: 8428: 8413:{\displaystyle Z(x)} 8395: 8321: 8310:{\displaystyle Z(y)} 8292: 8281:{\displaystyle Z(x)} 8263: 8243: 8223: 8212:{\displaystyle Z(y)} 8194: 8183:{\displaystyle Z(x)} 8165: 8129: 8109: 8064: 8028: 8001: 7974: 7947: 7860: 7836: 7816: 7796: 7785:{\displaystyle f(x)} 7767: 7623: 7603: 7577: 7536: 7483: 7456: 7428: 7408: 7366: 7346: 7322: 7268: 7210: 7156: 7083: 6965: 6936: 6888: 6798: 6738: 6710: 6669: 6628: 6591: 6571: 6547: 6524: 6504: 6457: 6437: 6417: 6300: 6274: 6232: 6206: 6186: 6105: 6085: 6053: 6014: 5994: 5970: 5950: 5912: 5868: 5842: 5788: 5729: 5686: 5655: 5591: 5550: 5524: 5504: 5445: 5411: 5391: 5371: 5250: 5230: 5210: 5177: 5151: 5116: 5096: 5045: 5010: 4905: 4873: 4853: 4818: 4783: 4748: 4713: 4589: 4558: 4521: 4501: 4481: 4258: 4128: 4119:of the second kind: 4059: 3953: 3775: 3587: 3474: 3454: 3419: 3140: 3081: 3057: 2951: 2917: 2788: 2738: 2629: 2508: 2362: 2221: 2124: 2092: 2034: 2014: 1987: 1946: 1879: 1875:are p.d. kernels on 1717: 1555: 1443: 1388: 1334: 1278: 1214: 1160: 1102: 1005: 958: 831: 774: 718: 653: 601: 527: 481: 410: 354: 221: 192: 144: 117: 8972:Covariance function 8520:and independent of 7748:representer theorem 6725:{\displaystyle x=y} 6221:{\displaystyle F=H} 5940: —  5906: —  4636: 4621: 4396: 4290: 4275: 4178: 3922: 3844: 3753: 3689: 3651: 3438: 3415:Kernels defined on 3396: 2851: 2755: 1479: 1428: 1263: 1238: 105:, and other areas. 8982:Integral transform 8938:Other applications 8874: 8775: 8754: 8698: 8674: 8650: 8550: 8530: 8510: 8490: 8470: 8443: 8410: 8381: 8307: 8278: 8249: 8229: 8209: 8180: 8151: 8115: 8095: 8050: 8014: 7987: 7960: 7933: 7846: 7822: 7802: 7782: 7714: 7609: 7589: 7563: 7515: 7469: 7442: 7414: 7388: 7352: 7332: 7308: 7250: 7196: 7142: 7053: 6946: 6922: 6864: 6783: 6722: 6696: 6655: 6611: 6577: 6553: 6530: 6510: 6478: 6443: 6423: 6403: 6286: 6260: 6218: 6192: 6172: 6091: 6071: 6039: 6000: 5976: 5956: 5938: 5918: 5904: 5880: 5854: 5828: 5772: 5712: 5661: 5634: 5577: 5536: 5510: 5490: 5431: 5397: 5377: 5317: 5236: 5216: 5196: 5163: 5137: 5102: 5079: 5031: 4993: 4938: 4891: 4859: 4839: 4804: 4769: 4734: 4699: 4622: 4607: 4571: 4540: 4507: 4487: 4451: 4382: 4276: 4261: 4223: 4164: 4101: 4030: 3939: 3910: 3884: 3832: 3807: 3762: 3741: 3722: 3677: 3639: 3619: 3574: 3460: 3439: 3422: 3403: 3334: 3126: 3063: 3038: 2930: 2903: 2824: 2774: 2741: 2731:Kernel generating 2718: 2612: 2504:Laplacian kernel: 2491: 2341: 2201: 2107: 2068: 2020: 2000: 1973: 1929: 1865: 1703: 1541: 1459: 1429: 1408: 1369: 1358: 1318: 1264: 1242: 1217: 1198: 1146: 1086: 978: 941: 814: 760: 704: 635: 580: 513: 464: 396: 324: 202: 178: 139:symmetric function 127: 103:information theory 83:integral equations 67:probability theory 9026:978-0-8218-1567-0 8977:Integral equation 8956:computer graphics 8952:rapid prototyping 8868: 8815: 8778:{\displaystyle K} 8677:{\displaystyle f} 8553:{\displaystyle f} 8533:{\displaystyle Z} 8513:{\displaystyle x} 8493:{\displaystyle x} 8252:{\displaystyle y} 8232:{\displaystyle x} 8118:{\displaystyle f} 8098:{\displaystyle E} 7825:{\displaystyle x} 7805:{\displaystyle f} 7727:Some applications 7712: 7612:{\displaystyle K} 7417:{\displaystyle K} 7355:{\displaystyle d} 7077: 7076: 6580:{\displaystyle d} 6556:{\displaystyle X} 6533:{\displaystyle d} 6513:{\displaystyle K} 6498:nearest neighbors 6446:{\displaystyle y} 6426:{\displaystyle x} 6195:{\displaystyle K} 6094:{\displaystyle F} 6003:{\displaystyle F} 5979:{\displaystyle K} 5959:{\displaystyle K} 5921:{\displaystyle K} 5664:{\displaystyle H} 5513:{\displaystyle H} 5400:{\displaystyle H} 5380:{\displaystyle X} 5239:{\displaystyle H} 5219:{\displaystyle K} 5105:{\displaystyle E} 4991: 4929: 4862:{\displaystyle x} 4681: 4510:{\displaystyle x} 4490:{\displaystyle K} 4475: 4474: 4374: 4335: 4247: 4246: 4211: 3923: 3903: 3875: 3845: 3825: 3798: 3713: 3691: 3610: 3569: 3521: 3066:{\displaystyle H} 2871: 2848: 2443: 2354:Gaussian kernel ( 2215:Polynomial kernel 2023:{\displaystyle K} 1488: 1485: 1343: 1047: 1044: 990:complex conjugate 970: 895: 702: 348: 347: 99:embedding problem 16:(Redirected from 9184: 9157: 9150: 9144: 9141: 9135: 9132: 9126: 9123: 9117: 9114: 9108: 9105: 9099: 9095: 9089: 9086: 9080: 9077: 9071: 9068: 9062: 9059: 9053: 9050: 9044: 9037: 9031: 9030: 9012: 8901:meshfree methods 8895:Meshfree methods 8883: 8881: 8880: 8875: 8873: 8869: 8864: 8863: 8862: 8846: 8836: 8831: 8816: 8808: 8784: 8782: 8781: 8776: 8763: 8761: 8760: 8755: 8753: 8752: 8743: 8742: 8724: 8723: 8707: 8705: 8704: 8699: 8697: 8696: 8683: 8681: 8680: 8675: 8659: 8657: 8656: 8651: 8649: 8648: 8636: 8635: 8559: 8557: 8556: 8551: 8539: 8537: 8536: 8531: 8519: 8517: 8516: 8511: 8499: 8497: 8496: 8491: 8479: 8477: 8476: 8471: 8469: 8468: 8452: 8450: 8449: 8444: 8419: 8417: 8416: 8411: 8390: 8388: 8387: 8382: 8316: 8314: 8313: 8308: 8287: 8285: 8284: 8279: 8258: 8256: 8255: 8250: 8239:is too close to 8238: 8236: 8235: 8230: 8218: 8216: 8215: 8210: 8189: 8187: 8186: 8181: 8160: 8158: 8157: 8152: 8150: 8149: 8124: 8122: 8121: 8116: 8104: 8102: 8101: 8096: 8088: 8087: 8059: 8057: 8056: 8051: 8046: 8045: 8023: 8021: 8020: 8015: 8013: 8012: 7996: 7994: 7993: 7988: 7986: 7985: 7969: 7967: 7966: 7961: 7959: 7958: 7942: 7940: 7939: 7934: 7926: 7925: 7907: 7906: 7888: 7887: 7875: 7874: 7855: 7853: 7852: 7847: 7845: 7844: 7831: 7829: 7828: 7823: 7811: 7809: 7808: 7803: 7791: 7789: 7788: 7783: 7723: 7721: 7720: 7715: 7713: 7648: 7618: 7616: 7615: 7610: 7598: 7596: 7595: 7590: 7572: 7570: 7569: 7564: 7524: 7522: 7521: 7516: 7514: 7513: 7504: 7503: 7478: 7476: 7475: 7470: 7468: 7467: 7451: 7449: 7448: 7443: 7441: 7423: 7421: 7420: 7415: 7397: 7395: 7394: 7389: 7378: 7377: 7361: 7359: 7358: 7353: 7341: 7339: 7338: 7333: 7331: 7330: 7317: 7315: 7314: 7309: 7304: 7303: 7259: 7257: 7256: 7251: 7243: 7242: 7232: 7227: 7205: 7203: 7202: 7197: 7195: 7187: 7186: 7168: 7167: 7151: 7149: 7148: 7143: 7138: 7137: 7128: 7127: 7109: 7108: 7096: 7071: 7062: 7060: 7059: 7054: 7043: 7042: 7030: 7029: 7014: 7013: 7004: 7003: 6993: 6988: 6959: 6955: 6953: 6952: 6947: 6945: 6944: 6931: 6929: 6928: 6923: 6921: 6913: 6912: 6903: 6902: 6873: 6871: 6870: 6865: 6792: 6790: 6789: 6784: 6731: 6729: 6728: 6723: 6705: 6703: 6702: 6697: 6664: 6662: 6661: 6656: 6621:which satisfies 6620: 6618: 6617: 6612: 6610: 6609: 6600: 6599: 6586: 6584: 6583: 6578: 6562: 6560: 6559: 6554: 6539: 6537: 6536: 6531: 6519: 6517: 6516: 6511: 6487: 6485: 6484: 6479: 6452: 6450: 6449: 6444: 6432: 6430: 6429: 6424: 6412: 6410: 6409: 6404: 6381: 6380: 6371: 6370: 6358: 6357: 6342: 6341: 6295: 6293: 6292: 6287: 6269: 6267: 6266: 6261: 6259: 6258: 6227: 6225: 6224: 6219: 6201: 6199: 6198: 6193: 6181: 6179: 6178: 6173: 6168: 6167: 6100: 6098: 6097: 6092: 6080: 6078: 6077: 6072: 6048: 6046: 6045: 6040: 6038: 6037: 6009: 6007: 6006: 6001: 5985: 5983: 5982: 5977: 5965: 5963: 5962: 5957: 5941: 5927: 5925: 5924: 5919: 5907: 5889: 5887: 5886: 5881: 5863: 5861: 5860: 5855: 5837: 5835: 5834: 5829: 5809: 5808: 5781: 5779: 5778: 5773: 5741: 5740: 5721: 5719: 5718: 5713: 5711: 5670: 5668: 5667: 5662: 5643: 5641: 5640: 5635: 5609: 5608: 5586: 5584: 5583: 5578: 5576: 5562: 5561: 5545: 5543: 5542: 5537: 5519: 5517: 5516: 5511: 5499: 5497: 5496: 5491: 5489: 5469: 5468: 5440: 5438: 5437: 5432: 5430: 5406: 5404: 5403: 5398: 5386: 5384: 5383: 5378: 5326: 5324: 5323: 5318: 5316: 5315: 5245: 5243: 5242: 5237: 5225: 5223: 5222: 5217: 5205: 5203: 5202: 5197: 5189: 5188: 5172: 5170: 5169: 5164: 5146: 5144: 5143: 5138: 5111: 5109: 5108: 5103: 5088: 5086: 5085: 5080: 5063: 5062: 5040: 5038: 5037: 5032: 5002: 5000: 4999: 4994: 4992: 4990: 4989: 4980: 4970: 4969: 4951: 4950: 4940: 4937: 4900: 4898: 4897: 4894:{\displaystyle } 4892: 4868: 4866: 4865: 4860: 4848: 4846: 4845: 4840: 4813: 4811: 4810: 4805: 4778: 4776: 4775: 4770: 4743: 4741: 4740: 4735: 4708: 4706: 4705: 4700: 4695: 4686: 4679: 4635: 4630: 4620: 4615: 4580: 4578: 4577: 4572: 4570: 4569: 4549: 4547: 4546: 4541: 4536: 4535: 4516: 4514: 4513: 4508: 4496: 4494: 4493: 4488: 4469: 4460: 4458: 4457: 4452: 4447: 4446: 4441: 4437: 4433: 4406: 4405: 4395: 4390: 4375: 4373: 4372: 4360: 4349: 4340: 4333: 4289: 4284: 4274: 4269: 4252: 4241: 4232: 4230: 4229: 4224: 4216: 4209: 4177: 4172: 4122: 4110: 4108: 4107: 4102: 4050:Mercer's theorem 4039: 4037: 4036: 4031: 4017: 4016: 4012: 3975: 3948: 3946: 3945: 3940: 3935: 3934: 3929: 3925: 3924: 3918: 3909: 3904: 3902: 3901: 3892: 3883: 3871: 3870: 3869: 3868: 3851: 3847: 3846: 3840: 3831: 3826: 3824: 3823: 3814: 3806: 3794: 3793: 3792: 3791: 3771: 3769: 3768: 3763: 3758: 3754: 3749: 3737: 3736: 3721: 3709: 3708: 3692: 3690: 3685: 3673: 3672: 3662: 3661: 3660: 3647: 3635: 3634: 3621: 3618: 3606: 3605: 3604: 3603: 3583: 3581: 3580: 3575: 3570: 3565: 3561: 3531: 3526: 3522: 3517: 3516: 3501: 3489: 3488: 3469: 3467: 3466: 3461: 3448: 3446: 3445: 3440: 3437: 3432: 3427: 3412: 3410: 3409: 3404: 3395: 3390: 3385: 3381: 3380: 3379: 3370: 3369: 3359: 3354: 3330: 3329: 3324: 3320: 3319: 3318: 3309: 3308: 3298: 3293: 3275: 3274: 3265: 3264: 3254: 3249: 3225: 3224: 3215: 3214: 3202: 3201: 3189: 3188: 3179: 3178: 3168: 3163: 3135: 3133: 3132: 3127: 3125: 3105: 3104: 3072: 3070: 3069: 3064: 3047: 3045: 3044: 3039: 3025: 2939: 2937: 2936: 2931: 2929: 2928: 2912: 2910: 2909: 2904: 2899: 2898: 2874: 2873: 2872: 2864: 2850: 2849: 2841: 2832: 2783: 2781: 2780: 2775: 2770: 2769: 2764: 2754: 2749: 2727: 2725: 2724: 2719: 2705: 2684: 2683: 2682: 2668: 2621: 2619: 2618: 2613: 2599: 2598: 2593: 2584: 2576: 2567: 2566: 2562: 2554: 2529: 2521: 2500: 2498: 2497: 2492: 2478: 2477: 2472: 2463: 2455: 2446: 2445: 2444: 2442: 2441: 2440: 2427: 2426: 2425: 2416: 2408: 2399: 2383: 2375: 2350: 2348: 2347: 2342: 2316: 2315: 2310: 2301: 2293: 2284: 2283: 2268: 2263: 2262: 2257: 2242: 2234: 2210: 2208: 2207: 2202: 2200: 2199: 2194: 2185: 2177: 2168: 2163: 2162: 2157: 2145: 2137: 2116: 2114: 2113: 2108: 2106: 2105: 2100: 2077: 2075: 2074: 2069: 2067: 2066: 2061: 2060: 2050: 2049: 2044: 2043: 2029: 2027: 2026: 2021: 2009: 2007: 2006: 2001: 1999: 1998: 1982: 1980: 1979: 1974: 1972: 1971: 1962: 1961: 1956: 1955: 1938: 1936: 1935: 1930: 1928: 1927: 1922: 1921: 1905: 1904: 1899: 1898: 1888: 1887: 1874: 1872: 1871: 1866: 1861: 1860: 1848: 1847: 1835: 1834: 1824: 1819: 1795: 1794: 1776: 1775: 1757: 1756: 1738: 1737: 1712: 1710: 1709: 1704: 1699: 1698: 1686: 1685: 1673: 1672: 1662: 1657: 1633: 1632: 1614: 1613: 1595: 1594: 1576: 1575: 1550: 1548: 1547: 1542: 1540: 1532: 1531: 1526: 1525: 1515: 1514: 1509: 1508: 1498: 1497: 1486: 1483: 1478: 1473: 1458: 1457: 1438: 1436: 1435: 1430: 1427: 1422: 1407: 1406: 1401: 1400: 1378: 1376: 1375: 1370: 1368: 1367: 1357: 1327: 1325: 1324: 1319: 1317: 1309: 1308: 1290: 1289: 1273: 1271: 1270: 1265: 1262: 1261: 1260: 1250: 1237: 1236: 1235: 1225: 1207: 1205: 1204: 1199: 1191: 1190: 1172: 1171: 1155: 1153: 1152: 1147: 1145: 1144: 1135: 1134: 1124: 1119: 1098:The conical sum 1095: 1093: 1092: 1087: 1085: 1077: 1076: 1067: 1066: 1057: 1056: 1045: 1042: 1038: 1037: 1036: 1020: 1019: 987: 985: 984: 979: 977: 976: 971: 963: 950: 948: 947: 942: 931: 930: 918: 917: 902: 901: 896: 888: 885: 884: 874: 869: 853: 848: 823: 821: 820: 815: 813: 805: 804: 786: 785: 769: 767: 766: 761: 759: 758: 749: 748: 730: 729: 713: 711: 710: 705: 703: 698: 678: 647:Hermitian kernel 644: 642: 641: 636: 634: 626: 625: 616: 615: 589: 587: 586: 581: 576: 575: 563: 562: 544: 543: 535: 522: 520: 519: 514: 493: 492: 473: 471: 470: 465: 463: 455: 454: 436: 435: 423: 405: 403: 402: 397: 395: 394: 385: 384: 366: 365: 342: 333: 331: 330: 325: 314: 313: 301: 300: 285: 284: 275: 274: 264: 259: 243: 238: 215: 211: 209: 208: 203: 201: 200: 187: 185: 184: 179: 177: 169: 168: 159: 158: 136: 134: 133: 128: 126: 125: 95:machine learning 63:Fourier analysis 21: 9192: 9191: 9187: 9186: 9185: 9183: 9182: 9181: 9172:Operator theory 9162: 9161: 9160: 9151: 9147: 9142: 9138: 9133: 9129: 9124: 9120: 9115: 9111: 9106: 9102: 9096: 9092: 9087: 9083: 9078: 9074: 9069: 9065: 9060: 9056: 9051: 9047: 9038: 9034: 9027: 9014: 9013: 9009: 9005: 8968: 8940: 8935: 8929: 8897: 8891: 8854: 8847: 8841: 8787: 8786: 8767: 8766: 8734: 8715: 8710: 8709: 8686: 8685: 8666: 8665: 8637: 8627: 8562: 8561: 8542: 8541: 8522: 8521: 8502: 8501: 8482: 8481: 8460: 8455: 8454: 8426: 8425: 8393: 8392: 8319: 8318: 8290: 8289: 8261: 8260: 8241: 8240: 8221: 8220: 8192: 8191: 8163: 8162: 8127: 8126: 8107: 8106: 8105:which replaces 8079: 8062: 8061: 8037: 8026: 8025: 8004: 7999: 7998: 7977: 7972: 7971: 7950: 7945: 7944: 7917: 7898: 7879: 7866: 7858: 7857: 7834: 7833: 7814: 7813: 7812:at a new point 7794: 7793: 7765: 7764: 7757: 7740: 7734: 7729: 7621: 7620: 7601: 7600: 7575: 7574: 7534: 7533: 7505: 7495: 7481: 7480: 7459: 7454: 7453: 7426: 7425: 7406: 7405: 7364: 7363: 7344: 7343: 7320: 7319: 7266: 7265: 7234: 7208: 7207: 7178: 7159: 7154: 7153: 7119: 7100: 7081: 7080: 7069: 7034: 7021: 7005: 6995: 6963: 6962: 6934: 6933: 6886: 6885: 6796: 6795: 6736: 6735: 6708: 6707: 6706:if and only if 6667: 6666: 6626: 6625: 6589: 6588: 6569: 6568: 6545: 6544: 6522: 6521: 6502: 6501: 6494: 6455: 6454: 6435: 6434: 6415: 6414: 6372: 6362: 6349: 6333: 6298: 6297: 6272: 6271: 6250: 6230: 6229: 6204: 6203: 6184: 6183: 6159: 6103: 6102: 6083: 6082: 6051: 6050: 6029: 6012: 6011: 5992: 5991: 5968: 5967: 5948: 5947: 5944: 5939: 5930: 5910: 5909: 5905: 5866: 5865: 5840: 5839: 5800: 5786: 5785: 5732: 5727: 5726: 5684: 5683: 5653: 5652: 5600: 5589: 5588: 5553: 5548: 5547: 5522: 5521: 5502: 5501: 5460: 5443: 5442: 5409: 5408: 5389: 5388: 5369: 5368: 5361: 5355: 5307: 5248: 5247: 5228: 5227: 5208: 5207: 5180: 5175: 5174: 5149: 5148: 5114: 5113: 5094: 5093: 5054: 5043: 5042: 5008: 5007: 4981: 4961: 4942: 4941: 4903: 4902: 4871: 4870: 4851: 4850: 4816: 4815: 4781: 4780: 4746: 4745: 4711: 4710: 4587: 4586: 4561: 4556: 4555: 4527: 4519: 4518: 4517:is continuous, 4499: 4498: 4479: 4478: 4467: 4397: 4381: 4377: 4376: 4364: 4256: 4255: 4239: 4126: 4125: 4057: 4056: 4052: 4046: 4005: 3982: 3968: 3951: 3950: 3893: 3890: 3886: 3885: 3860: 3855: 3815: 3812: 3808: 3783: 3778: 3773: 3772: 3728: 3727: 3723: 3697: 3664: 3663: 3652: 3626: 3622: 3595: 3590: 3585: 3584: 3554: 3532: 3509: 3502: 3496: 3477: 3472: 3471: 3452: 3451: 3417: 3416: 3371: 3361: 3339: 3335: 3310: 3300: 3266: 3256: 3234: 3230: 3229: 3216: 3206: 3193: 3180: 3170: 3138: 3137: 3096: 3079: 3078: 3055: 3054: 2949: 2948: 2920: 2915: 2914: 2890: 2852: 2786: 2785: 2759: 2736: 2735: 2653: 2627: 2626: 2588: 2536: 2506: 2505: 2467: 2432: 2428: 2417: 2400: 2390: 2360: 2359: 2305: 2275: 2252: 2219: 2218: 2189: 2152: 2122: 2121: 2120:Linear kernel: 2095: 2090: 2089: 2085: 2054: 2037: 2032: 2031: 2012: 2011: 1990: 1985: 1984: 1949: 1944: 1943: 1915: 1892: 1877: 1876: 1852: 1839: 1826: 1786: 1767: 1748: 1729: 1715: 1714: 1690: 1677: 1664: 1624: 1605: 1586: 1567: 1553: 1552: 1519: 1502: 1489: 1449: 1441: 1440: 1394: 1386: 1385: 1359: 1332: 1331: 1300: 1281: 1276: 1275: 1274:is p.d., given 1252: 1227: 1212: 1211: 1182: 1163: 1158: 1157: 1156:is p.d., given 1136: 1126: 1100: 1099: 1048: 1021: 1011: 1003: 1002: 998: 961: 956: 955: 922: 909: 886: 876: 829: 828: 796: 777: 772: 771: 740: 721: 716: 715: 679: 651: 650: 599: 598: 567: 554: 530: 525: 524: 484: 479: 478: 446: 427: 408: 407: 376: 357: 352: 351: 340: 305: 292: 276: 266: 219: 218: 190: 189: 142: 141: 115: 114: 111: 79:moment problems 71:operator theory 39:operator theory 35: 32:Integral kernel 28: 23: 22: 15: 12: 11: 5: 9190: 9188: 9180: 9179: 9177:Hilbert spaces 9174: 9164: 9163: 9159: 9158: 9145: 9136: 9127: 9118: 9109: 9100: 9090: 9081: 9072: 9063: 9054: 9045: 9032: 9025: 9006: 9004: 9001: 9000: 8999: 8994: 8989: 8984: 8979: 8974: 8967: 8964: 8962:environments. 8939: 8936: 8928: 8925: 8890: 8887: 8886: 8885: 8872: 8867: 8861: 8857: 8853: 8850: 8844: 8840: 8835: 8830: 8827: 8824: 8820: 8814: 8811: 8806: 8803: 8800: 8797: 8794: 8774: 8751: 8746: 8741: 8737: 8733: 8730: 8727: 8722: 8718: 8695: 8673: 8647: 8644: 8640: 8634: 8630: 8626: 8623: 8620: 8617: 8614: 8611: 8608: 8605: 8602: 8599: 8596: 8593: 8590: 8587: 8584: 8581: 8578: 8575: 8572: 8569: 8549: 8529: 8509: 8489: 8480:, is added to 8467: 8463: 8442: 8439: 8436: 8433: 8422: 8421: 8409: 8406: 8403: 8400: 8380: 8377: 8374: 8371: 8368: 8365: 8362: 8359: 8356: 8353: 8350: 8347: 8344: 8341: 8338: 8335: 8332: 8329: 8326: 8306: 8303: 8300: 8297: 8277: 8274: 8271: 8268: 8248: 8228: 8208: 8205: 8202: 8199: 8179: 8176: 8173: 8170: 8148: 8143: 8140: 8137: 8134: 8114: 8094: 8091: 8086: 8082: 8078: 8075: 8072: 8069: 8049: 8044: 8040: 8036: 8033: 8011: 8007: 7984: 7980: 7957: 7953: 7932: 7929: 7924: 7920: 7916: 7913: 7910: 7905: 7901: 7897: 7894: 7891: 7886: 7882: 7878: 7873: 7869: 7865: 7843: 7821: 7801: 7781: 7778: 7775: 7772: 7756: 7753: 7733: 7730: 7728: 7725: 7711: 7708: 7705: 7702: 7699: 7696: 7693: 7690: 7687: 7684: 7681: 7678: 7675: 7672: 7669: 7666: 7663: 7660: 7657: 7654: 7651: 7646: 7643: 7640: 7637: 7634: 7631: 7628: 7608: 7588: 7585: 7582: 7562: 7559: 7556: 7553: 7550: 7547: 7544: 7541: 7512: 7508: 7502: 7498: 7494: 7491: 7488: 7466: 7462: 7440: 7436: 7433: 7413: 7387: 7384: 7381: 7376: 7371: 7351: 7329: 7307: 7302: 7297: 7294: 7291: 7288: 7285: 7282: 7279: 7276: 7273: 7249: 7246: 7241: 7237: 7231: 7226: 7223: 7220: 7216: 7194: 7190: 7185: 7181: 7177: 7174: 7171: 7166: 7162: 7141: 7136: 7131: 7126: 7122: 7118: 7115: 7112: 7107: 7103: 7099: 7095: 7091: 7088: 7079:holds for any 7075: 7074: 7065: 7063: 7052: 7049: 7046: 7041: 7037: 7033: 7028: 7024: 7020: 7017: 7012: 7008: 7002: 6998: 6992: 6987: 6984: 6981: 6978: 6975: 6971: 6943: 6920: 6916: 6911: 6906: 6901: 6896: 6893: 6875: 6874: 6863: 6860: 6857: 6854: 6851: 6848: 6845: 6842: 6839: 6836: 6833: 6830: 6827: 6824: 6821: 6818: 6815: 6812: 6809: 6806: 6803: 6793: 6782: 6779: 6776: 6773: 6770: 6767: 6764: 6761: 6758: 6755: 6752: 6749: 6746: 6743: 6733: 6721: 6718: 6715: 6695: 6692: 6689: 6686: 6683: 6680: 6677: 6674: 6654: 6651: 6648: 6645: 6642: 6639: 6636: 6633: 6608: 6603: 6598: 6576: 6552: 6529: 6520:and distances 6509: 6493: 6490: 6477: 6474: 6471: 6468: 6465: 6462: 6442: 6422: 6402: 6399: 6396: 6393: 6390: 6387: 6384: 6379: 6375: 6369: 6365: 6361: 6356: 6352: 6348: 6345: 6340: 6336: 6332: 6329: 6326: 6323: 6320: 6317: 6314: 6311: 6308: 6305: 6285: 6282: 6279: 6257: 6253: 6249: 6246: 6243: 6240: 6237: 6217: 6214: 6211: 6191: 6171: 6166: 6162: 6158: 6155: 6152: 6149: 6146: 6143: 6140: 6137: 6134: 6131: 6128: 6125: 6122: 6119: 6116: 6113: 6110: 6090: 6070: 6067: 6064: 6061: 6058: 6036: 6032: 6028: 6025: 6022: 6019: 5999: 5975: 5955: 5934: 5917: 5900: 5892: 5891: 5879: 5876: 5873: 5853: 5850: 5847: 5827: 5824: 5821: 5818: 5815: 5812: 5807: 5803: 5799: 5796: 5793: 5783: 5771: 5768: 5765: 5762: 5759: 5756: 5753: 5750: 5747: 5744: 5739: 5735: 5710: 5706: 5703: 5700: 5697: 5694: 5691: 5660: 5633: 5630: 5627: 5624: 5621: 5618: 5615: 5612: 5607: 5603: 5599: 5596: 5587:is defined by 5575: 5571: 5568: 5565: 5560: 5556: 5535: 5532: 5529: 5509: 5488: 5484: 5481: 5478: 5475: 5472: 5467: 5463: 5459: 5456: 5453: 5450: 5429: 5425: 5422: 5419: 5416: 5396: 5376: 5354: 5351: 5314: 5310: 5306: 5303: 5300: 5297: 5294: 5291: 5288: 5285: 5282: 5279: 5276: 5273: 5270: 5267: 5264: 5261: 5258: 5255: 5235: 5215: 5195: 5192: 5187: 5183: 5162: 5159: 5156: 5136: 5133: 5130: 5127: 5124: 5121: 5101: 5078: 5075: 5072: 5069: 5066: 5061: 5057: 5053: 5050: 5030: 5027: 5024: 5021: 5018: 5015: 4988: 4984: 4979: 4976: 4973: 4968: 4964: 4960: 4957: 4954: 4949: 4945: 4936: 4932: 4928: 4925: 4922: 4919: 4916: 4913: 4910: 4890: 4887: 4884: 4881: 4878: 4858: 4838: 4835: 4832: 4829: 4826: 4823: 4803: 4800: 4797: 4794: 4791: 4788: 4768: 4765: 4762: 4759: 4756: 4753: 4733: 4730: 4727: 4724: 4721: 4718: 4698: 4694: 4689: 4685: 4678: 4675: 4672: 4669: 4666: 4663: 4660: 4657: 4654: 4651: 4648: 4645: 4642: 4639: 4634: 4629: 4625: 4619: 4614: 4610: 4606: 4603: 4600: 4597: 4594: 4568: 4564: 4539: 4534: 4530: 4526: 4506: 4486: 4473: 4472: 4463: 4461: 4450: 4445: 4440: 4436: 4432: 4427: 4424: 4421: 4418: 4415: 4412: 4409: 4404: 4400: 4394: 4389: 4385: 4380: 4371: 4367: 4363: 4358: 4355: 4352: 4348: 4343: 4339: 4332: 4329: 4326: 4323: 4320: 4317: 4314: 4311: 4308: 4305: 4302: 4299: 4296: 4293: 4288: 4283: 4279: 4273: 4268: 4264: 4245: 4244: 4235: 4233: 4222: 4219: 4215: 4208: 4205: 4202: 4199: 4196: 4193: 4190: 4187: 4184: 4181: 4176: 4171: 4167: 4163: 4160: 4157: 4154: 4151: 4148: 4145: 4142: 4139: 4136: 4133: 4100: 4097: 4094: 4091: 4088: 4085: 4082: 4079: 4076: 4073: 4070: 4067: 4064: 4045: 4042: 4041: 4040: 4029: 4026: 4023: 4020: 4015: 4011: 4008: 4004: 4001: 3998: 3995: 3992: 3989: 3985: 3981: 3978: 3974: 3971: 3967: 3964: 3961: 3958: 3938: 3933: 3928: 3921: 3917: 3913: 3907: 3900: 3896: 3889: 3882: 3878: 3874: 3867: 3863: 3858: 3854: 3850: 3843: 3839: 3835: 3829: 3822: 3818: 3811: 3805: 3801: 3797: 3790: 3786: 3781: 3761: 3757: 3752: 3748: 3744: 3740: 3735: 3731: 3726: 3720: 3716: 3712: 3707: 3704: 3700: 3695: 3688: 3684: 3680: 3676: 3671: 3667: 3659: 3655: 3650: 3646: 3642: 3638: 3633: 3629: 3625: 3617: 3613: 3609: 3602: 3598: 3593: 3573: 3568: 3564: 3560: 3557: 3553: 3550: 3547: 3544: 3541: 3538: 3535: 3529: 3525: 3520: 3515: 3512: 3508: 3505: 3499: 3495: 3492: 3487: 3484: 3480: 3459: 3436: 3431: 3426: 3413: 3402: 3399: 3394: 3389: 3384: 3378: 3374: 3368: 3364: 3358: 3353: 3350: 3347: 3343: 3338: 3333: 3328: 3323: 3317: 3313: 3307: 3303: 3297: 3292: 3289: 3286: 3282: 3278: 3273: 3269: 3263: 3259: 3253: 3248: 3245: 3242: 3238: 3233: 3228: 3223: 3219: 3213: 3209: 3205: 3200: 3196: 3192: 3187: 3183: 3177: 3173: 3167: 3162: 3159: 3156: 3153: 3150: 3146: 3124: 3120: 3117: 3114: 3111: 3108: 3103: 3099: 3095: 3092: 3089: 3086: 3062: 3051: 3050: 3049: 3037: 3034: 3031: 3028: 3024: 3020: 3017: 3014: 3011: 3007: 3004: 3001: 2998: 2995: 2992: 2989: 2986: 2983: 2980: 2977: 2974: 2971: 2968: 2965: 2962: 2959: 2956: 2945: 2927: 2923: 2902: 2897: 2893: 2889: 2886: 2883: 2880: 2877: 2870: 2867: 2862: 2859: 2855: 2847: 2844: 2839: 2836: 2831: 2827: 2823: 2820: 2817: 2814: 2811: 2808: 2805: 2802: 2799: 2796: 2793: 2773: 2768: 2763: 2758: 2753: 2748: 2744: 2733:Sobolev spaces 2729: 2717: 2714: 2711: 2708: 2704: 2700: 2697: 2694: 2691: 2687: 2681: 2677: 2674: 2671: 2667: 2663: 2660: 2656: 2652: 2649: 2646: 2643: 2640: 2637: 2634: 2623: 2611: 2608: 2605: 2602: 2597: 2592: 2587: 2583: 2579: 2575: 2570: 2565: 2561: 2557: 2553: 2549: 2546: 2543: 2539: 2535: 2532: 2528: 2524: 2520: 2516: 2513: 2502: 2490: 2487: 2484: 2481: 2476: 2471: 2466: 2462: 2458: 2454: 2449: 2439: 2435: 2431: 2424: 2420: 2415: 2411: 2407: 2403: 2397: 2393: 2389: 2386: 2382: 2378: 2374: 2370: 2367: 2352: 2340: 2337: 2334: 2331: 2328: 2325: 2322: 2319: 2314: 2309: 2304: 2300: 2296: 2292: 2287: 2282: 2278: 2274: 2271: 2267: 2261: 2256: 2251: 2248: 2245: 2241: 2237: 2233: 2229: 2226: 2212: 2198: 2193: 2188: 2184: 2180: 2176: 2171: 2167: 2161: 2156: 2151: 2148: 2144: 2140: 2136: 2132: 2129: 2104: 2099: 2084: 2081: 2080: 2079: 2065: 2059: 2053: 2048: 2042: 2019: 1997: 1993: 1970: 1965: 1960: 1954: 1940: 1926: 1920: 1914: 1911: 1908: 1903: 1897: 1891: 1886: 1864: 1859: 1855: 1851: 1846: 1842: 1838: 1833: 1829: 1823: 1818: 1815: 1812: 1808: 1804: 1801: 1798: 1793: 1789: 1785: 1782: 1779: 1774: 1770: 1766: 1763: 1760: 1755: 1751: 1747: 1744: 1741: 1736: 1732: 1728: 1725: 1722: 1702: 1697: 1693: 1689: 1684: 1680: 1676: 1671: 1667: 1661: 1656: 1653: 1650: 1646: 1642: 1639: 1636: 1631: 1627: 1623: 1620: 1617: 1612: 1608: 1604: 1601: 1598: 1593: 1589: 1585: 1582: 1579: 1574: 1570: 1566: 1563: 1560: 1539: 1535: 1530: 1524: 1518: 1513: 1507: 1501: 1496: 1492: 1482: 1477: 1472: 1469: 1466: 1462: 1456: 1452: 1448: 1426: 1421: 1418: 1415: 1411: 1405: 1399: 1393: 1382: 1381: 1380: 1366: 1362: 1356: 1353: 1350: 1346: 1342: 1339: 1328: 1316: 1312: 1307: 1303: 1299: 1296: 1293: 1288: 1284: 1259: 1255: 1249: 1245: 1241: 1234: 1230: 1224: 1220: 1208: 1197: 1194: 1189: 1185: 1181: 1178: 1175: 1170: 1166: 1143: 1139: 1133: 1129: 1123: 1118: 1115: 1112: 1108: 1084: 1080: 1075: 1070: 1065: 1060: 1055: 1051: 1041: 1035: 1031: 1028: 1024: 1018: 1014: 1010: 997: 994: 975: 969: 966: 952: 951: 940: 937: 934: 929: 925: 921: 916: 912: 908: 905: 900: 894: 891: 883: 879: 873: 868: 865: 862: 858: 852: 847: 844: 841: 837: 812: 808: 803: 799: 795: 792: 789: 784: 780: 757: 752: 747: 743: 739: 736: 733: 728: 724: 701: 697: 694: 691: 688: 685: 682: 676: 673: 670: 667: 664: 661: 658: 633: 629: 624: 619: 614: 609: 606: 579: 574: 570: 566: 561: 557: 553: 550: 547: 542: 539: 534: 512: 509: 506: 503: 499: 496: 491: 487: 462: 458: 453: 449: 445: 442: 439: 434: 430: 426: 422: 418: 415: 393: 388: 383: 379: 375: 372: 369: 364: 360: 350:holds for all 346: 345: 336: 334: 323: 320: 317: 312: 308: 304: 299: 295: 291: 288: 283: 279: 273: 269: 263: 258: 255: 252: 248: 242: 237: 234: 231: 227: 199: 176: 172: 167: 162: 157: 152: 149: 124: 110: 107: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 9189: 9178: 9175: 9173: 9170: 9169: 9167: 9155: 9149: 9146: 9140: 9137: 9131: 9128: 9122: 9119: 9113: 9110: 9104: 9101: 9094: 9091: 9085: 9082: 9076: 9073: 9067: 9064: 9058: 9055: 9049: 9046: 9042: 9036: 9033: 9028: 9022: 9018: 9011: 9008: 9002: 8998: 8997:Kernel method 8995: 8993: 8990: 8988: 8985: 8983: 8980: 8978: 8975: 8973: 8970: 8969: 8965: 8963: 8959: 8957: 8953: 8949: 8945: 8937: 8934: 8926: 8924: 8922: 8918: 8914: 8910: 8906: 8902: 8896: 8888: 8870: 8865: 8859: 8855: 8851: 8848: 8842: 8838: 8833: 8828: 8825: 8822: 8818: 8812: 8809: 8804: 8798: 8792: 8772: 8744: 8739: 8735: 8731: 8728: 8725: 8720: 8716: 8671: 8663: 8662: 8661: 8645: 8642: 8638: 8632: 8628: 8624: 8615: 8609: 8606: 8600: 8594: 8588: 8585: 8579: 8576: 8573: 8567: 8547: 8527: 8507: 8487: 8465: 8461: 8437: 8431: 8404: 8398: 8372: 8366: 8363: 8357: 8351: 8345: 8342: 8336: 8333: 8330: 8324: 8301: 8295: 8272: 8266: 8246: 8226: 8203: 8197: 8174: 8168: 8141: 8138: 8135: 8132: 8112: 8084: 8080: 8073: 8067: 8042: 8038: 8031: 8009: 8005: 7982: 7978: 7955: 7951: 7922: 7918: 7911: 7908: 7903: 7899: 7892: 7884: 7880: 7876: 7871: 7867: 7819: 7799: 7776: 7770: 7762: 7761: 7760: 7754: 7752: 7749: 7745: 7739: 7738:Kernel method 7731: 7726: 7724: 7706: 7703: 7700: 7694: 7691: 7685: 7682: 7679: 7673: 7670: 7667: 7661: 7658: 7655: 7649: 7644: 7638: 7635: 7632: 7626: 7606: 7586: 7583: 7580: 7560: 7557: 7551: 7548: 7545: 7539: 7531: 7526: 7510: 7500: 7496: 7489: 7486: 7464: 7460: 7434: 7431: 7411: 7402: 7400: 7399:isometrically 7382: 7379: 7349: 7295: 7292: 7289: 7283: 7280: 7277: 7261: 7247: 7244: 7239: 7235: 7229: 7224: 7221: 7218: 7214: 7188: 7183: 7179: 7175: 7172: 7169: 7164: 7160: 7139: 7129: 7124: 7120: 7116: 7113: 7110: 7105: 7101: 7097: 7089: 7086: 7073: 7066: 7064: 7050: 7047: 7039: 7035: 7031: 7026: 7022: 7015: 7010: 7006: 7000: 6996: 6990: 6985: 6982: 6979: 6976: 6973: 6969: 6961: 6960: 6957: 6904: 6894: 6891: 6883: 6878: 6861: 6855: 6852: 6849: 6843: 6840: 6834: 6831: 6828: 6822: 6819: 6813: 6810: 6807: 6801: 6794: 6780: 6774: 6771: 6768: 6762: 6759: 6753: 6750: 6747: 6741: 6734: 6719: 6716: 6713: 6693: 6690: 6684: 6681: 6678: 6672: 6652: 6649: 6643: 6640: 6637: 6631: 6624: 6623: 6622: 6601: 6574: 6566: 6550: 6541: 6527: 6507: 6499: 6491: 6489: 6472: 6469: 6466: 6460: 6440: 6420: 6397: 6394: 6391: 6385: 6382: 6377: 6367: 6363: 6359: 6354: 6350: 6343: 6338: 6327: 6318: 6312: 6283: 6280: 6277: 6255: 6251: 6247: 6241: 6215: 6212: 6209: 6189: 6169: 6164: 6153: 6144: 6138: 6126: 6120: 6117: 6114: 6108: 6088: 6068: 6062: 6059: 6034: 6026: 6023: 6020: 5997: 5987: 5973: 5953: 5943: 5933: 5929: 5915: 5899: 5895: 5877: 5874: 5871: 5851: 5848: 5845: 5822: 5816: 5813: 5805: 5801: 5797: 5794: 5784: 5769: 5766: 5763: 5757: 5754: 5751: 5745: 5737: 5733: 5725: 5724: 5723: 5701: 5698: 5695: 5692: 5689: 5681: 5676: 5672: 5658: 5650: 5645: 5628: 5622: 5619: 5613: 5605: 5601: 5594: 5566: 5563: 5558: 5554: 5533: 5530: 5527: 5507: 5479: 5476: 5473: 5470: 5465: 5457: 5454: 5451: 5420: 5417: 5414: 5394: 5374: 5365: 5360: 5352: 5350: 5347: 5345: 5341: 5337: 5333: 5328: 5312: 5301: 5298: 5295: 5289: 5286: 5283: 5277: 5271: 5265: 5262: 5259: 5256: 5253: 5233: 5213: 5193: 5190: 5185: 5181: 5160: 5157: 5154: 5131: 5128: 5125: 5119: 5099: 5090: 5073: 5070: 5067: 5059: 5055: 5051: 5048: 5028: 5025: 5019: 5013: 5004: 4986: 4982: 4974: 4966: 4962: 4955: 4947: 4943: 4934: 4930: 4926: 4920: 4917: 4914: 4908: 4885: 4882: 4879: 4856: 4836: 4833: 4827: 4821: 4798: 4795: 4792: 4786: 4766: 4763: 4757: 4751: 4731: 4728: 4722: 4716: 4696: 4687: 4673: 4667: 4661: 4655: 4649: 4646: 4643: 4637: 4632: 4627: 4623: 4617: 4612: 4608: 4604: 4598: 4592: 4584: 4566: 4562: 4553: 4532: 4528: 4504: 4484: 4471: 4464: 4462: 4448: 4443: 4438: 4434: 4422: 4416: 4410: 4402: 4398: 4392: 4387: 4383: 4378: 4369: 4365: 4361: 4356: 4353: 4350: 4341: 4327: 4321: 4315: 4309: 4303: 4300: 4297: 4291: 4286: 4281: 4277: 4271: 4266: 4262: 4254: 4253: 4250: 4243: 4236: 4234: 4220: 4217: 4203: 4197: 4191: 4188: 4185: 4179: 4174: 4169: 4165: 4161: 4158: 4152: 4146: 4143: 4137: 4131: 4124: 4123: 4120: 4118: 4114: 4095: 4092: 4089: 4083: 4080: 4074: 4071: 4068: 4062: 4051: 4043: 4027: 4024: 4021: 4018: 4009: 4006: 4002: 3999: 3993: 3990: 3987: 3983: 3979: 3972: 3969: 3965: 3962: 3956: 3936: 3931: 3926: 3919: 3915: 3911: 3905: 3898: 3894: 3887: 3880: 3876: 3872: 3865: 3861: 3856: 3852: 3848: 3841: 3837: 3833: 3827: 3820: 3816: 3809: 3803: 3799: 3795: 3788: 3784: 3779: 3759: 3755: 3750: 3746: 3742: 3738: 3733: 3729: 3724: 3718: 3714: 3710: 3705: 3702: 3698: 3693: 3686: 3682: 3678: 3674: 3669: 3665: 3657: 3648: 3644: 3640: 3636: 3631: 3627: 3615: 3611: 3607: 3600: 3596: 3591: 3571: 3566: 3558: 3555: 3548: 3545: 3539: 3533: 3527: 3523: 3518: 3513: 3510: 3506: 3503: 3497: 3493: 3490: 3485: 3482: 3478: 3457: 3434: 3429: 3414: 3400: 3397: 3392: 3387: 3376: 3372: 3366: 3362: 3356: 3351: 3348: 3345: 3341: 3331: 3326: 3321: 3315: 3311: 3305: 3301: 3295: 3290: 3287: 3284: 3280: 3276: 3271: 3267: 3261: 3257: 3251: 3246: 3243: 3240: 3236: 3231: 3226: 3221: 3211: 3207: 3203: 3198: 3194: 3185: 3181: 3175: 3171: 3165: 3160: 3157: 3154: 3151: 3148: 3144: 3115: 3112: 3109: 3106: 3101: 3093: 3090: 3087: 3076: 3075:Hilbert space 3060: 3052: 3035: 3032: 3029: 3026: 3018: 3015: 3012: 3009: 3005: 2996: 2993: 2990: 2984: 2978: 2975: 2972: 2966: 2963: 2960: 2954: 2946: 2943: 2925: 2921: 2895: 2887: 2884: 2881: 2868: 2865: 2860: 2857: 2853: 2845: 2842: 2837: 2834: 2829: 2821: 2818: 2815: 2809: 2803: 2800: 2797: 2791: 2766: 2751: 2746: 2742: 2734: 2730: 2715: 2712: 2709: 2706: 2698: 2695: 2692: 2689: 2685: 2675: 2672: 2669: 2661: 2658: 2654: 2650: 2644: 2641: 2638: 2632: 2625:Abel kernel: 2624: 2609: 2606: 2603: 2600: 2595: 2585: 2577: 2568: 2555: 2544: 2541: 2537: 2533: 2522: 2511: 2503: 2488: 2485: 2482: 2479: 2474: 2464: 2456: 2447: 2437: 2433: 2429: 2422: 2409: 2395: 2391: 2387: 2376: 2365: 2357: 2353: 2338: 2335: 2332: 2329: 2326: 2323: 2320: 2317: 2312: 2302: 2294: 2285: 2280: 2272: 2269: 2259: 2246: 2235: 2224: 2216: 2213: 2196: 2186: 2178: 2169: 2159: 2149: 2138: 2127: 2119: 2118: 2102: 2087: 2086: 2082: 2063: 2051: 2046: 2017: 1995: 1991: 1963: 1958: 1941: 1924: 1912: 1909: 1906: 1901: 1889: 1857: 1853: 1849: 1844: 1840: 1831: 1827: 1821: 1816: 1813: 1810: 1806: 1802: 1791: 1787: 1783: 1780: 1777: 1772: 1768: 1761: 1753: 1749: 1745: 1742: 1739: 1734: 1730: 1720: 1695: 1691: 1687: 1682: 1678: 1669: 1665: 1659: 1654: 1651: 1648: 1644: 1640: 1629: 1625: 1621: 1618: 1615: 1610: 1606: 1599: 1591: 1587: 1583: 1580: 1577: 1572: 1568: 1558: 1528: 1516: 1511: 1499: 1494: 1490: 1480: 1475: 1470: 1467: 1464: 1454: 1450: 1424: 1419: 1416: 1413: 1403: 1383: 1364: 1360: 1348: 1340: 1337: 1329: 1310: 1305: 1301: 1297: 1294: 1291: 1286: 1282: 1257: 1253: 1247: 1243: 1239: 1232: 1228: 1222: 1218: 1209: 1195: 1192: 1187: 1183: 1179: 1176: 1173: 1168: 1164: 1141: 1137: 1131: 1127: 1121: 1116: 1113: 1110: 1106: 1097: 1096: 1068: 1058: 1053: 1049: 1039: 1029: 1026: 1016: 1012: 1000: 999: 995: 993: 991: 973: 964: 938: 935: 927: 923: 919: 914: 910: 903: 898: 889: 881: 877: 871: 866: 863: 860: 856: 850: 845: 842: 839: 835: 827: 826: 825: 806: 801: 797: 793: 790: 787: 782: 778: 750: 745: 741: 737: 734: 731: 726: 722: 692: 689: 686: 680: 674: 668: 665: 662: 656: 648: 617: 607: 604: 595: 593: 572: 568: 564: 559: 555: 548: 545: 540: 537: 507: 497: 494: 489: 485: 475: 456: 451: 447: 443: 440: 437: 432: 428: 424: 416: 413: 386: 381: 377: 373: 370: 367: 362: 358: 344: 337: 335: 321: 318: 310: 306: 302: 297: 293: 286: 281: 277: 271: 267: 261: 256: 253: 250: 246: 240: 235: 232: 229: 225: 217: 216: 213: 160: 150: 147: 140: 108: 106: 104: 100: 96: 92: 88: 84: 80: 76: 72: 68: 64: 60: 56: 52: 48: 44: 40: 33: 19: 9148: 9139: 9130: 9121: 9112: 9103: 9093: 9084: 9075: 9066: 9057: 9048: 9035: 9016: 9010: 8960: 8941: 8898: 8423: 7758: 7741: 7530:pseudometric 7527: 7403: 7263: 7078: 7067: 6881: 6880: 6876: 6563:, we mean a 6542: 6495: 5988: 5945: 5935: 5931: 5901: 5897: 5893: 5679: 5678: 5674: 5648: 5647: 5366: 5362: 5348: 5329: 5091: 5005: 4476: 4465: 4248: 4237: 4053: 1210:The product 988:denotes the 953: 646: 645:is called a 596: 476: 349: 338: 112: 55:James Mercer 42: 36: 8921:collocation 5147:defined on 4744:except for 4583:eigenvalues 592:eigenvalues 9166:Categories 9003:References 7479:such that 7206:such that 6882:Definition 5838:, for all 5722:such that 5680:Definition 5649:Definition 5520:. For any 5387:be a set, 4709:satisfies 4113:S. Bochner 4048:See also: 2356:RBF kernel 1330:The limit 109:Definition 8852:− 8819:∑ 8745:∈ 8729:… 8639:δ 8629:σ 8607:⋅ 8462:σ 8432:ϵ 8364:⋅ 8142:∈ 7832:of a set 7668:− 7584:≠ 7435:∈ 7296:∈ 7215:∑ 7189:∈ 7173:… 7130:∈ 7114:… 7090:∈ 7048:≤ 7016:ψ 6970:∑ 6915:→ 6905:× 6892:ψ 6820:≤ 6650:≥ 6602:× 6322:Φ 6307:Φ 6281:∈ 6236:Φ 6148:Φ 6133:Φ 6066:→ 6057:Φ 6027:⋅ 6021:⋅ 5875:∈ 5849:∈ 5767:∈ 5761:∀ 5752:∈ 5746:⋅ 5705:→ 5699:× 5598:↦ 5570:→ 5531:∈ 5483:→ 5477:× 5458:⋅ 5452:⋅ 5424:→ 5332:E. Cartan 5296:⋅ 5257:∈ 5191:∈ 5158:× 5052:∈ 5026:≥ 4983:λ 4963:ψ 4944:ψ 4931:∑ 4834:≥ 4624:∫ 4609:∫ 4563:λ 4529:ψ 4399:ψ 4384:∫ 4366:λ 4357:∑ 4278:∫ 4263:∫ 4198:φ 4166:∫ 4162:λ 4159:− 4147:φ 4093:− 4022:α 4007:θ 4000:θ 3994:ψ 3991:α 3988:− 3970:θ 3963:θ 3912:θ 3906:− 3895:θ 3877:∑ 3857:ψ 3834:θ 3828:− 3817:θ 3800:∑ 3780:ψ 3743:θ 3739:− 3730:θ 3715:∑ 3699:ψ 3679:θ 3666:θ 3641:θ 3637:− 3628:θ 3612:∑ 3597:χ 3592:ψ 3556:θ 3540:θ 3528:− 3511:θ 3504:θ 3479:ψ 3458:χ 3398:≥ 3342:∑ 3281:∑ 3237:∑ 3145:∑ 3119:→ 3113:× 3094:⋅ 3088:⋅ 3030:α 3019:∈ 2994:− 2985:α 2979:⁡ 2926:ν 2892:‖ 2885:− 2879:‖ 2861:− 2838:− 2826:‖ 2819:− 2813:‖ 2710:α 2699:∈ 2673:− 2662:α 2659:− 2604:α 2586:∈ 2564:‖ 2556:− 2548:‖ 2545:α 2542:− 2483:σ 2465:∈ 2434:σ 2419:‖ 2410:− 2402:‖ 2396:− 2336:≥ 2324:≥ 2303:∈ 2187:∈ 2117:include: 2052:× 1964:⊂ 1913:× 1910:⋯ 1907:× 1807:∑ 1781:… 1743:… 1645:∏ 1619:… 1581:… 1534:→ 1517:× 1355:∞ 1352:→ 1311:∈ 1295:… 1240:… 1193:≥ 1184:λ 1177:… 1165:λ 1128:λ 1107:∑ 1079:→ 1069:× 1030:∈ 968:¯ 965:ξ 936:≥ 893:¯ 890:ξ 878:ξ 857:∑ 836:∑ 807:∈ 798:ξ 791:… 779:ξ 751:∈ 735:… 700:¯ 628:→ 618:× 505:∀ 457:∈ 441:… 417:∈ 387:∈ 371:… 319:≥ 247:∑ 226:∑ 171:→ 161:× 8966:See also 6270:for all 5651:: Space 5340:M. Krein 5041:for all 4010:′ 3973:′ 3920:′ 3842:′ 3751:′ 3687:′ 3649:′ 3559:′ 3514:′ 3383:‖ 3337:‖ 2913:, where 9098:69–164. 8944:kriging 6296:. Then 5937:Theorem 5903:Theorem 5336:H. Weyl 4044:History 2940:is the 9023:  6665:, and 6565:metric 6228:, and 5441:, and 4680:  4554:, and 4477:where 4334:  4210:  1487:  1484:  1046:  1043:  954:where 5782:, and 3073:is a 49:or a 9021:ISBN 8954:and 8915:and 8905:PDEs 8288:and 8190:and 7573:for 7152:and 6433:and 5864:and 5367:Let 4729:> 4025:> 3033:> 2976:sinc 2713:> 2607:> 2486:> 1942:Let 1713:and 113:Let 89:for 7970:at 7070:1.4 6956:if 6587:on 4869:on 4468:1.3 4240:1.2 3053:If 2358:): 2030:to 2010:of 1384:If 1345:lim 649:if 474:. 341:1.1 212:if 37:In 9168:: 8923:. 8911:, 8660:. 7525:. 7260:. 6540:. 5089:. 4028:0. 2784:: 2217:: 824:, 594:. 406:, 101:, 97:, 93:, 85:, 81:, 77:, 73:, 69:, 65:, 9029:. 8871:) 8866:h 8860:i 8856:x 8849:x 8843:( 8839:K 8834:n 8829:1 8826:= 8823:i 8813:n 8810:1 8805:= 8802:) 8799:x 8796:( 8793:f 8773:K 8750:X 8740:n 8736:x 8732:, 8726:, 8721:1 8717:x 8694:X 8672:f 8646:y 8643:x 8633:2 8625:+ 8622:] 8619:) 8616:y 8613:( 8610:Z 8604:) 8601:x 8598:( 8595:Z 8592:[ 8589:E 8586:= 8583:) 8580:y 8577:, 8574:x 8571:( 8568:K 8548:f 8528:Z 8508:x 8488:x 8466:2 8441:) 8438:x 8435:( 8408:) 8405:x 8402:( 8399:Z 8379:] 8376:) 8373:y 8370:( 8367:Z 8361:) 8358:x 8355:( 8352:Z 8349:[ 8346:E 8343:= 8340:) 8337:y 8334:, 8331:x 8328:( 8325:K 8305:) 8302:y 8299:( 8296:Z 8276:) 8273:x 8270:( 8267:Z 8247:y 8227:x 8207:) 8204:y 8201:( 8198:Z 8178:) 8175:x 8172:( 8169:Z 8147:X 8139:y 8136:, 8133:x 8113:f 8093:] 8090:) 8085:i 8081:x 8077:( 8074:Z 8071:[ 8068:E 8048:) 8043:i 8039:x 8035:( 8032:Z 8010:i 8006:x 7983:i 7979:x 7956:i 7952:f 7931:) 7928:) 7923:i 7919:x 7915:( 7912:f 7909:, 7904:i 7900:x 7896:( 7893:= 7890:) 7885:i 7881:f 7877:, 7872:i 7868:x 7864:( 7842:X 7820:x 7800:f 7780:) 7777:x 7774:( 7771:f 7710:) 7707:y 7704:, 7701:y 7698:( 7695:K 7692:+ 7689:) 7686:y 7683:, 7680:x 7677:( 7674:K 7671:2 7665:) 7662:x 7659:, 7656:x 7653:( 7650:K 7645:= 7642:) 7639:y 7636:, 7633:x 7630:( 7627:d 7607:K 7587:y 7581:x 7561:0 7558:= 7555:) 7552:y 7549:, 7546:x 7543:( 7540:d 7511:n 7507:) 7501:n 7497:K 7493:( 7490:= 7487:K 7465:n 7461:K 7439:N 7432:n 7412:K 7386:) 7383:d 7380:, 7375:X 7370:( 7350:d 7328:X 7306:} 7301:X 7293:x 7290:: 7287:) 7284:x 7281:, 7278:x 7275:( 7272:{ 7248:0 7245:= 7240:i 7236:c 7230:n 7225:1 7222:= 7219:i 7193:R 7184:n 7180:c 7176:, 7170:, 7165:1 7161:c 7140:, 7135:X 7125:n 7121:x 7117:, 7111:, 7106:1 7102:x 7098:, 7094:N 7087:n 7072:) 7068:( 7051:0 7045:) 7040:j 7036:x 7032:, 7027:i 7023:x 7019:( 7011:j 7007:c 7001:i 6997:c 6991:n 6986:1 6983:= 6980:j 6977:, 6974:i 6942:X 6919:R 6910:X 6900:X 6895:: 6862:. 6859:) 6856:z 6853:, 6850:y 6847:( 6844:d 6841:+ 6838:) 6835:y 6832:, 6829:x 6826:( 6823:d 6817:) 6814:z 6811:, 6808:x 6805:( 6802:d 6781:, 6778:) 6775:x 6772:, 6769:y 6766:( 6763:d 6760:= 6757:) 6754:y 6751:, 6748:x 6745:( 6742:d 6732:, 6720:y 6717:= 6714:x 6694:0 6691:= 6688:) 6685:y 6682:, 6679:x 6676:( 6673:d 6653:0 6647:) 6644:y 6641:, 6638:x 6635:( 6632:d 6607:X 6597:X 6575:d 6551:X 6528:d 6508:K 6476:) 6473:y 6470:, 6467:x 6464:( 6461:K 6441:y 6421:x 6401:) 6398:y 6395:, 6392:x 6389:( 6386:K 6383:= 6378:H 6374:) 6368:y 6364:K 6360:, 6355:x 6351:K 6347:( 6344:= 6339:F 6335:) 6331:) 6328:y 6325:( 6319:, 6316:) 6313:x 6310:( 6304:( 6284:X 6278:x 6256:x 6252:K 6248:= 6245:) 6242:x 6239:( 6216:H 6213:= 6210:F 6190:K 6170:. 6165:F 6161:) 6157:) 6154:y 6151:( 6145:, 6142:) 6139:x 6136:( 6130:( 6127:= 6124:) 6121:y 6118:, 6115:x 6112:( 6109:K 6089:F 6069:F 6063:X 6060:: 6035:F 6031:) 6024:, 6018:( 5998:F 5974:K 5954:K 5916:K 5890:. 5878:X 5872:x 5852:H 5846:f 5826:) 5823:x 5820:( 5817:f 5814:= 5811:) 5806:x 5802:K 5798:, 5795:f 5792:( 5770:X 5764:x 5758:, 5755:H 5749:) 5743:( 5738:x 5734:K 5709:R 5702:X 5696:X 5693:: 5690:K 5659:H 5632:) 5629:x 5626:( 5623:f 5620:= 5617:) 5614:f 5611:( 5606:x 5602:e 5595:f 5574:R 5567:H 5564:: 5559:x 5555:e 5534:X 5528:x 5508:H 5487:R 5480:H 5474:H 5471:: 5466:H 5462:) 5455:, 5449:( 5428:R 5421:X 5418:: 5415:f 5395:H 5375:X 5313:H 5309:) 5305:) 5302:y 5299:, 5293:( 5290:K 5287:, 5284:f 5281:( 5278:= 5275:) 5272:y 5269:( 5266:f 5263:, 5260:H 5254:f 5234:H 5214:K 5194:E 5186:i 5182:x 5161:E 5155:E 5135:) 5132:y 5129:, 5126:x 5123:( 5120:K 5100:E 5077:] 5074:b 5071:, 5068:a 5065:[ 5060:1 5056:L 5049:x 5029:0 5023:) 5020:x 5017:( 5014:J 4987:n 4978:) 4975:t 4972:( 4967:n 4959:) 4956:s 4953:( 4948:n 4935:n 4927:= 4924:) 4921:t 4918:, 4915:s 4912:( 4909:K 4889:] 4886:b 4883:, 4880:a 4877:[ 4857:x 4837:0 4831:) 4828:x 4825:( 4822:J 4802:) 4799:t 4796:, 4793:s 4790:( 4787:K 4767:0 4764:= 4761:) 4758:t 4755:( 4752:x 4732:0 4726:) 4723:x 4720:( 4717:J 4697:t 4693:d 4688:s 4684:d 4677:) 4674:t 4671:( 4668:x 4665:) 4662:s 4659:( 4656:x 4653:) 4650:t 4647:, 4644:s 4641:( 4638:K 4633:b 4628:a 4618:b 4613:a 4605:= 4602:) 4599:x 4596:( 4593:J 4567:n 4538:} 4533:n 4525:{ 4505:x 4485:K 4470:) 4466:( 4449:, 4444:2 4439:] 4435:s 4431:d 4426:) 4423:s 4420:( 4417:x 4414:) 4411:s 4408:( 4403:n 4393:b 4388:a 4379:[ 4370:n 4362:1 4354:= 4351:t 4347:d 4342:s 4338:d 4331:) 4328:t 4325:( 4322:x 4319:) 4316:s 4313:( 4310:x 4307:) 4304:t 4301:, 4298:s 4295:( 4292:K 4287:b 4282:a 4272:b 4267:a 4242:) 4238:( 4221:. 4218:t 4214:d 4207:) 4204:t 4201:( 4195:) 4192:t 4189:, 4186:s 4183:( 4180:K 4175:b 4170:a 4156:) 4153:s 4150:( 4144:= 4141:) 4138:s 4135:( 4132:f 4099:) 4096:y 4090:x 4087:( 4084:f 4081:= 4078:) 4075:y 4072:, 4069:x 4066:( 4063:K 4019:, 4014:) 4003:, 3997:( 3984:e 3980:= 3977:) 3966:, 3960:( 3957:K 3937:, 3932:2 3927:| 3916:i 3899:i 3888:| 3881:i 3873:= 3866:2 3862:H 3853:, 3849:| 3838:i 3821:i 3810:| 3804:i 3796:= 3789:1 3785:H 3760:, 3756:| 3747:i 3734:i 3725:| 3719:i 3711:= 3706:V 3703:T 3694:, 3683:i 3675:+ 3670:i 3658:2 3654:) 3645:i 3632:i 3624:( 3616:i 3608:= 3601:2 3572:, 3567:2 3563:) 3552:( 3549:H 3546:+ 3543:) 3537:( 3534:H 3524:) 3519:2 3507:+ 3498:( 3494:H 3491:= 3486:D 3483:J 3435:d 3430:+ 3425:R 3401:0 3393:2 3388:H 3377:i 3373:x 3367:i 3363:c 3357:n 3352:1 3349:= 3346:i 3332:= 3327:H 3322:) 3316:j 3312:x 3306:j 3302:c 3296:n 3291:1 3288:= 3285:j 3277:, 3272:i 3268:x 3262:i 3258:c 3252:n 3247:1 3244:= 3241:i 3232:( 3227:= 3222:H 3218:) 3212:j 3208:x 3204:, 3199:i 3195:x 3191:( 3186:j 3182:c 3176:i 3172:c 3166:n 3161:1 3158:= 3155:j 3152:, 3149:i 3123:R 3116:H 3110:H 3107:: 3102:H 3098:) 3091:, 3085:( 3061:H 3048:. 3036:0 3027:, 3023:R 3016:y 3013:, 3010:x 3006:, 3003:) 3000:) 2997:y 2991:x 2988:( 2982:( 2973:= 2970:) 2967:y 2964:, 2961:x 2958:( 2955:K 2944:. 2922:B 2901:) 2896:2 2888:y 2882:x 2876:( 2869:2 2866:d 2858:k 2854:B 2846:2 2843:d 2835:k 2830:2 2822:y 2816:x 2810:= 2807:) 2804:y 2801:, 2798:x 2795:( 2792:K 2772:) 2767:d 2762:R 2757:( 2752:k 2747:2 2743:W 2728:. 2716:0 2707:, 2703:R 2696:y 2693:, 2690:x 2686:, 2680:| 2676:y 2670:x 2666:| 2655:e 2651:= 2648:) 2645:y 2642:, 2639:x 2636:( 2633:K 2622:. 2610:0 2601:, 2596:d 2591:R 2582:y 2578:, 2574:x 2569:, 2560:y 2552:x 2538:e 2534:= 2531:) 2527:y 2523:, 2519:x 2515:( 2512:K 2501:. 2489:0 2480:, 2475:d 2470:R 2461:y 2457:, 2453:x 2448:, 2438:2 2430:2 2423:2 2414:y 2406:x 2392:e 2388:= 2385:) 2381:y 2377:, 2373:x 2369:( 2366:K 2351:. 2339:1 2333:n 2330:, 2327:0 2321:r 2318:, 2313:d 2308:R 2299:y 2295:, 2291:x 2286:, 2281:n 2277:) 2273:r 2270:+ 2266:y 2260:T 2255:x 2250:( 2247:= 2244:) 2240:y 2236:, 2232:x 2228:( 2225:K 2211:. 2197:d 2192:R 2183:y 2179:, 2175:x 2170:, 2166:y 2160:T 2155:x 2150:= 2147:) 2143:y 2139:, 2135:x 2131:( 2128:K 2103:d 2098:R 2064:0 2058:X 2047:0 2041:X 2018:K 1996:0 1992:K 1969:X 1959:0 1953:X 1939:. 1925:n 1919:X 1902:1 1896:X 1890:= 1885:X 1863:) 1858:i 1854:y 1850:, 1845:i 1841:x 1837:( 1832:i 1828:K 1822:n 1817:1 1814:= 1811:i 1803:= 1800:) 1797:) 1792:n 1788:y 1784:, 1778:, 1773:1 1769:y 1765:( 1762:, 1759:) 1754:n 1750:x 1746:, 1740:, 1735:1 1731:x 1727:( 1724:( 1721:K 1701:) 1696:i 1692:y 1688:, 1683:i 1679:x 1675:( 1670:i 1666:K 1660:n 1655:1 1652:= 1649:i 1641:= 1638:) 1635:) 1630:n 1626:y 1622:, 1616:, 1611:1 1607:y 1603:( 1600:, 1597:) 1592:n 1588:x 1584:, 1578:, 1573:1 1569:x 1565:( 1562:( 1559:K 1538:R 1529:i 1523:X 1512:i 1506:X 1500:: 1495:i 1491:K 1481:, 1476:n 1471:1 1468:= 1465:i 1461:) 1455:i 1451:K 1447:( 1425:n 1420:1 1417:= 1414:i 1410:) 1404:i 1398:X 1392:( 1365:n 1361:K 1349:n 1341:= 1338:K 1315:N 1306:n 1302:a 1298:, 1292:, 1287:1 1283:a 1258:n 1254:a 1248:n 1244:K 1233:1 1229:a 1223:1 1219:K 1196:0 1188:n 1180:, 1174:, 1169:1 1142:i 1138:K 1132:i 1122:n 1117:1 1114:= 1111:i 1083:R 1074:X 1064:X 1059:: 1054:i 1050:K 1040:, 1034:N 1027:i 1023:) 1017:i 1013:K 1009:( 974:j 939:0 933:) 928:j 924:x 920:, 915:i 911:x 907:( 904:K 899:j 882:i 872:n 867:1 864:= 861:j 851:n 846:1 843:= 840:i 811:C 802:n 794:, 788:, 783:1 756:X 746:n 742:x 738:, 732:, 727:1 723:x 696:) 693:x 690:, 687:y 684:( 681:K 675:= 672:) 669:y 666:, 663:x 660:( 657:K 632:C 623:X 613:X 608:: 605:K 578:) 573:j 569:x 565:, 560:i 556:x 552:( 549:K 546:= 541:j 538:i 533:K 511:) 508:i 502:( 498:0 495:= 490:i 486:c 461:R 452:n 448:c 444:, 438:, 433:1 429:c 425:, 421:N 414:n 392:X 382:n 378:x 374:, 368:, 363:1 359:x 343:) 339:( 322:0 316:) 311:j 307:x 303:, 298:i 294:x 290:( 287:K 282:j 278:c 272:i 268:c 262:n 257:1 254:= 251:j 241:n 236:1 233:= 230:i 198:X 175:R 166:X 156:X 151:: 148:K 123:X 34:. 20:)

Index

Positive-definite kernel function
Integral kernel
operator theory
positive-definite function
positive-definite matrix
James Mercer
integral operator equations
Fourier analysis
probability theory
operator theory
complex function-theory
moment problems
integral equations
boundary-value problems
partial differential equations
machine learning
embedding problem
information theory
symmetric function
eigenvalues
complex conjugate
Polynomial kernel
RBF kernel
Sobolev spaces
Bessel function of the third kind
Hilbert space
Mercer's theorem
S. Bochner
Fredholm integral equations
orthonormal eigenfunctions

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