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Witt group

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For global fields there is a local-to-global principle: two global fields are Witt equivalent if and only if there is a bijection between their places such that the corresponding local fields are Witt equivalent. In particular, two number fields
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is a related construction generated by isometry classes of nonsingular quadratic spaces with addition given by orthogonal sum and multiplication given by tensor product. Since two spaces that differ by a hyperbolic plane are not identified in
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to the graded Witt ring. Milnor showed also that this homomorphism sends elements divisible by 2 to zero and that it is surjective. In the same paper he made a conjecture that this homomorphism is an isomorphism for all fields
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of forms. It is additively generated by the classes of one-dimensional forms. Although classes may contain spaces of different dimension, the parity of the dimension is constant across a class and so rk :
3226: 1510: 2853: 2562: 3401: 3168: 1643: 2785: 3342: 3116: 2759: 3068: 2288: 3296: 3025: 2815: 2703: 3270: 3250: 286: 1132: 2987:{\displaystyle \langle \langle a_{1},\ldots ,a_{n}\rangle \rangle =(\langle a_{1}\rangle -\langle 1\rangle )\cdots (\langle a_{n}\rangle -\langle 1\rangle )} 2546:{\displaystyle 0\rightarrow \mathbf {Z} \rightarrow W(\mathbf {Q} )\rightarrow \mathbf {Z} /2\oplus \bigoplus _{p\neq 2}W(\mathbf {F} _{p})\rightarrow 0\ } 962: 4243:
of the sphere spectrum, In: Axiomatic, Enriched and Motivic Homotopy Theory, pp. 219–260, J.P.C. Greenlees (ed.), 2004 Kluwer Academic Publishers.
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Certain invariants of a quadratic form can be regarded as functions on Witt classes. We have seen that dimension mod 2 is a function on classes: the
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is real, then the nilpotent elements are precisely those of finite additive order, and these in turn are the forms all of whose signatures are zero;
2241:{\displaystyle (d_{1},e_{1},f_{1})\cdot (d_{2},e_{2},f_{2})=(d_{1}^{e_{2}}d_{2}^{e_{1}},e_{1}e_{2},^{1+e_{1}e_{2}}f_{1}^{e_{2}}f_{2}^{e_{1}})\ .} 216: 4266:
Perlis, R.; Szymiczek, K.; Conner, P.E.; Litherland, R. (1994). "Matching Witts with global fields". In Jacob, William B.; et al. (eds.).
771: 4532: 4498: 3173: 1552: 897: 105: 4637: 4570: 4456: 4422: 4380: 4279: 1444: 329: 3423:, the inverse for the addition needs to be introduced formally through the construction that was discovered by Grothendieck (see 893: 4448: 1563:. The invariants of a form over a number field are precisely the dimension, discriminant, all local Hasse invariants and the 4490: 4414: 4271: 1564: 494: 2820: 707: 2279: 2650:{\displaystyle W(\mathbf {Q} )\cong \mathbf {Z} \oplus \mathbf {Z} /2\oplus \bigoplus _{p\neq 2}W(\mathbf {F} _{p})\ } 108:, the non-degenerate two-dimensional symmetric bilinear form with a norm 0 vector. Each class is represented by the 3473: 3469: 3436: 623: 619: 482:
are the elements for which some signature is zero; otherwise, the zero-divisors are exactly the fundamental ideal.
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The Grothendieck-Witt ring of a local field with maximal ideal of norm congruent to 1 modulo 4 is isomorphic to
2263:) obtained by mapping a class to discriminant, rank mod 2, and the sequence of Hasse invariants. The kernel is 4677: 4125: 2706: 89: 81: 1948:{\displaystyle (d_{1},e_{1},f_{1})+(d_{2},e_{2},f_{2})=((-1)^{e_{1}e_{2}}d_{1}d_{2},e_{1}+e_{2},f_{1}f_{2})} 301: 93: 62: 3513:
with trivial multiplication in the second component. The element (1, 0) corresponds to the quadratic form ⟨
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is of characteristic not equal to 2, so that we may identify symmetric bilinear forms and quadratic forms.
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The Grothendieck-Witt ring of a local field with maximal ideal of norm congruent to 3 modulo 4 it is
3357:(of characteristic different from 2). This became known as the Milnor conjecture on quadratic forms. 2438: 664: 167: 4593: 4402: 3670: 3662: 3301: 3073: 2716: 418: 293: 203: 50: 4186: 3424: 3361: 3033: 2366:{\displaystyle W(\mathbf {Q} )\rightarrow W(\mathbf {R} )\oplus \prod _{p}W(\mathbf {Q} _{p})\ .} 542: 160: 113: 3403:, leading to increased understanding of the structure of quadratic forms over arbitrary fields. 3683:
The resulting groups (and generalizations thereof) are known as the even-dimensional symmetric
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We make this concrete, and compute the image, by using the "second residue homomorphism" W(
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of non-degenerate symmetric bilinear forms, with the group operation corresponding to the
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are +1, that the value on acomplex places is +1 and that the product of all the terms in
1279:{\displaystyle (d_{1},e_{1})\cdot (d_{2},e_{2})=(d_{1}^{e_{2}}d_{2}^{e_{1}},e_{1}e_{2}).} 4398: 3752: 3666: 3448: 3255: 3235: 1560: 386: 271: 4330:
Czogała, A. (1999). "Higher degree tame Hilbert-symbol equivalence of number fields".
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The Witt ring of a local field with maximal ideal of norm congruent to 3 modulo 4 is (
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Orlov, Dmitry; Vishik, Alexander; Voevodsky, Vladimir (2007), "An exact sequence for
3572: 1301:) to this obtained by mapping a class to discriminant and rank mod 2. The kernel is 1121:{\displaystyle (d_{1},e_{1})+(d_{2},e_{2})=((-1)^{e_{1}e_{2}}d_{1}d_{2},e_{1}+e_{2})} 727: 562: 398: 343:), though the term "Witt ring" is often also used for a completely different ring of 312:
is the exponent of the torsion in the Witt group, if this is finite, or ∞ otherwise.
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Balmer, Paul (2005). "Witt groups". In Friedlander, Eric M.; Grayson, D. R. (eds.).
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if and only if this is an isomorphism. The hyperbolic spaces generate an ideal in
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in +1. Let be the sequence of Hilbert symbols: it satisfies the conditions on
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The triple of discriminant, rank mod 2 and Hasse invariant defines a map from
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Szymiczek, Kazimierz (1997). "Hilbert-symbol equivalence of number fields".
1362: 527: 109: 4661: 3741:) being the Witt group of (−1)-quadratic forms (skew-symmetric); symmetric 3452: 3643:. Some variations and extensions of this condition, such as "tame degree 261:{\displaystyle \langle \!\langle w\rangle \!\rangle =\langle 1,-w\rangle } 3684: 3656: 414: 3501:
The Grothendieck-Witt ring of any finite field of odd characteristic is
3344:) to zero. This means that this mapping defines a homomorphism from the 875:{\displaystyle \mathbf {Z} _{8}/\langle 2s,2t,s^{2},t^{2},st-4\rangle .} 4525:
Algebra. Volume II: Fields with Structure, Algebras and Advanced Topics
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is not formally real, the fundamental ideal is the only prime ideal of
4493:, vol. 211 (Revised third ed.), New York: Springer-Verlag, 4191: 3674: 2672:
be a field of characteristic not equal to 2. The powers of the ideal
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Grothendieck-Witt ring and motivic stable homotopy groups of spheres
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is again a well-defined function on Witt classes with values in the
3221:{\displaystyle \langle \langle a_{1},\ldots ,a_{n}\rangle \rangle } 4591:(1936), "Theorie der quadratischen Formen in beliebigen Korpern", 4561:. Ergebnisse der Mathematik und ihrer Grenzgebiete. Vol. 73. 597:-th power of the fundamental ideal is additively generated by the 3360:
The conjecture was proved by Dmitry Orlov, Alexander Vishik and
3730:) being the Witt group of (1)-quadratic forms (symmetric), and 3575:
is isomorphic to the motivic stable homotopy group of spheres π
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gives the Grothendieck-Witt ring the additional structure of a
1622:, subject to the condition that all but finitely many terms of 4268:
Recent advances in real algebraic geometry and quadratic forms
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to be the 2-adic valuation of the discriminant, taken mod 2).
1505:{\displaystyle W(K)=W(k)\oplus \langle \pi \rangle \cdot W(k)} 1309:
may be regarded as classifying graded quadratic extensions of
4375:. Series in Pure Mathematics. Vol. 2. World Scientific. 4413:. University Lecture Series. Vol. 28. Providence, RI: 2270:
The symbol ring is a realisation of the Brauer-Wall group.
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are Witt equivalent if and only if there is a bijection
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and maps Steinberg elements (elements such that for some
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congruent to 1 modulo 4 is isomorphic to the group ring (
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to define the ring product. This is sometimes called the
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Hilbert symbol equivalence", have also been studied.
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with respective to the ordering. The Witt ring is a
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To discuss the structure of this ring we assume that
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Witt groups can also be defined in the same way for
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of forms of even dimension ("fundamental ideal") in
2848:{\displaystyle \langle a\rangle -\langle 1\rangle } 1618:a sequence of elements ±1 indexed by the places of 4373:A Survey of Trace Forms of Algebraic Number Fields 4123:(1970), "Algebraic K-theory and quadratic forms", 3395: 3336: 3290: 3264: 3244: 3220: 3162: 3110: 3062: 3019: 2986: 2847: 2809: 2779: 2753: 2697: 2649: 2545: 2365: 2251:Then there is a surjective ring homomorphism from 2240: 1947: 1637:We define addition and multiplication as follows: 1504: 1278: 1120: 874: 280: 260: 100:if one can be obtained from the other by adding a 233: 223: 4270:. Contemp. Math. Vol. 155. Providence, RI: 2817:considered as an element of the Witt ring. Then 4594:Journal für die reine und angewandte Mathematik 4451:. Vol. 67. American Mathematical Society. 1361:of characteristic not equal to 2. There is an 956:. Addition and multiplication are defined by: 357:The kernel of the rank mod 2 homomorphism is a 170:in the Witt group have order a power of 2; the 3030:in a 1970 paper proved that the mapping from 4411:Cohomological invariants in Galois cohomology 8: 4221:Garibaldi, Merkurjev & Serre (2003) p.63 4047:Garibaldi, Merkurjev & Serre (2003) p.64 3571:showed that the Grothendieck-Witt ring of a 3215: 3212: 3180: 3177: 2978: 2972: 2966: 2953: 2941: 2935: 2929: 2916: 2907: 2904: 2872: 2869: 2842: 2836: 2830: 2824: 2774: 2768: 2660:where the first component is the signature. 1484: 1478: 866: 807: 255: 240: 234: 230: 224: 220: 4664:in the Springer encyclopedia of mathematics 4445:Introduction to Quadratic Forms over Fields 2859:and correspondingly a product of the form 4190: 3989: 3987: 3985: 3983: 3910: 3908: 3837:Milnor & Husemoller (1973) p. 72 3816:Milnor & Husemoller (1973) p. 66 3804:Milnor & Husemoller (1973) p. 65 3786:Milnor & Husemoller (1973) p. 14 3372: 3371: 3369: 3364:in 1996 (published in 2007) for the case 3322: 3309: 3303: 3277: 3257: 3237: 3206: 3187: 3175: 3151: 3132: 3123: 3096: 3087: 3081: 3075: 3054: 3044: 3035: 3008: 3002: 2960: 2923: 2898: 2879: 2867: 2822: 2801: 2792: 2766: 2739: 2730: 2724: 2718: 2681: 2635: 2630: 2611: 2596: 2591: 2583: 2572: 2564: 2525: 2520: 2501: 2486: 2481: 2470: 2456: 2448: 2348: 2343: 2330: 2315: 2298: 2290: 2221: 2216: 2211: 2199: 2194: 2189: 2177: 2167: 2156: 2146: 2133: 2117: 2107: 2092: 2087: 2082: 2070: 2065: 2060: 2041: 2028: 2015: 1996: 1983: 1970: 1961: 1936: 1926: 1911: 1901: 1896: 1874: 1864: 1845: 1832: 1816: 1803: 1790: 1780: 1768: 1758: 1753: 1725: 1712: 1699: 1680: 1667: 1654: 1645: 1446: 1264: 1254: 1239: 1234: 1229: 1217: 1212: 1207: 1188: 1175: 1156: 1143: 1134: 1109: 1096: 1083: 1073: 1061: 1051: 1046: 1018: 1005: 986: 973: 964: 845: 832: 802: 781: 776: 773: 273: 218: 3964: 3962: 3960: 3958: 3956: 3854: 3852: 3755:, forming one of the three terms of the 4175:with applications to quadratic forms", 3779: 2556:which can be written as an isomorphism 541:and constitute the minimal prime ideal 489:is an ordered field with positive cone 405:if and only if there are finitely many 92:. We say that two spaces equipped with 3880: 3878: 3812: 3810: 2713:, that is the direct sum of quotients 3868: 3866: 3864: 3824: 3822: 3396:{\displaystyle {\textrm {char}}(k)=0} 3163:{\displaystyle (a_{1},\ldots ,a_{n})} 7: 3595:if their Witt rings are isomorphic. 3521:is not a square in the finite field. 3427:). There is a natural homomorphism 2709:and one may consider the associated 104:, that is, zero or more copies of a 3641:degree 2 Hilbert symbol equivalence 2282:implies that there is an injection 898:Hasse invariant of a quadratic form 4065:Conner & Perlis (1984) p.16-17 2407:) we obtain a group homomorphism ∂ 1357:, uniformiser π and residue field 61:whose elements are represented by 25: 3697:) and even-dimensional quadratic 2780:{\displaystyle \langle a\rangle } 1380:) which lifts the diagonal form ⟨ 505:defines a ring homomorphism from 330:tensor product of quadratic forms 30:For Witt groups in the theory of 3487:is isomorphic to the group ring 2631: 2592: 2584: 2573: 2521: 2482: 2471: 2457: 2344: 2316: 2299: 777: 4449:Graduate Studies in Mathematics 4074:Conner & Perlis (1984) p.18 4056:Conner & Perlis (1984) p.16 4020:Conner & Perlis (1984) p.12 3751:-groups are central objects in 3435:given by dimension: a field is 2664:Witt ring and Milnor's K-theory 497:holds for quadratic forms over 421:in the multiplicative group of 288:a non-zero sum of squares. If 3483:The Grothendieck-Witt ring of 3464:The Grothendieck-Witt ring of 3384: 3378: 3157: 3125: 3051: 3037: 2981: 2950: 2944: 2913: 2692: 2686: 2641: 2626: 2577: 2569: 2534: 2531: 2516: 2478: 2475: 2467: 2461: 2453: 2354: 2339: 2320: 2312: 2306: 2303: 2295: 2229: 2153: 2126: 2053: 2047: 2008: 2002: 1963: 1942: 1919: 1893: 1883: 1854: 1851: 1825: 1750: 1740: 1737: 1731: 1692: 1686: 1647: 1499: 1493: 1472: 1466: 1457: 1451: 1270: 1200: 1194: 1168: 1162: 1136: 1115: 1043: 1033: 1030: 1024: 998: 992: 966: 799: 787: 762:is of order 32 and is given by 436:and consists precisely of the 365:, of the Witt ring termed the 1: 4491:Graduate Texts in Mathematics 4415:American Mathematical Society 4332:Abh. Math. Sem. Univ. Hamburg 4272:American Mathematical Society 3719:-groups are 4-periodic, with 3498:is a cyclic group of order 2. 3337:{\displaystyle a_{i}+a_{j}=1} 3111:{\displaystyle I^{n}/I^{n+1}} 2754:{\displaystyle I^{n}/I^{n+1}} 1567:coming from real embeddings. 526:. These prime ideals are in 409:; that is, if the squares in 88:will be assumed to be finite- 4230:Lam (2005) p.36, Theorem 3.5 2394:). Composed with the map W( 1547:. For quadratic forms over 904:of the field of definition. 517:, with kernel a prime ideal 3063:{\displaystyle (k^{*})^{n}} 1535:Witt ring of a number field 896:is also well-defined. The 4694: 3654: 3591:Two fields are said to be 3474:quadratically closed field 3470:algebraically closed field 2274:Witt ring of the rationals 1341:Witt ring of a local field 624:quadratically closed field 620:algebraically closed field 495:Sylvester's law of inertia 29: 4371:; Perlis, Robert (1984). 4239:, On the motivic stable π 4201:10.4007/annals.2007.165.1 3769:Reduced height of a field 577:and the set of orderings 296:, then the Witt group is 210:; it is generated by the 102:metabolic quadratic space 4559:Symmetric Bilinear Forms 4126:Inventiones Mathematicae 3923:Lorenz (2008) p. 36 3902:Lorenz (2008) p. 33 3884:Lorenz (2008) p. 31 3872:Lorenz (2008) p. 35 3828:Lorenz (2008) p. 37 3795:Lorenz (2008) p. 30 3619:and a group isomorphism 2663: 1582:), as a set of triples ( 328:structure, by using the 94:symmetric bilinear forms 3637:reciprocity equivalence 3291:{\displaystyle i\neq j} 2280:Hasse–Minkowski theorem 1293:ring homomorphism from 561:). The bijection is a 463:has Krull dimension 1. 166:The elements of finite 84:not equal to two. All 4523:Lorenz, Falko (2008). 3941:Lam (2005) pp. 277–280 3932:Lam (2005) p. 282 3914:Lam (2005) p. 280 3858:Lam (2005) p. 395 3846:Lam (2005) p. 260 3757:surgery exact sequence 3611:between the places of 3447:is the quotient. The 3413:Grothendieck-Witt ring 3407:Grothendieck-Witt ring 3397: 3338: 3292: 3266: 3246: 3222: 3164: 3112: 3064: 3021: 3020:{\displaystyle I^{n}.} 2988: 2849: 2811: 2810:{\displaystyle ax^{2}} 2787:be the quadratic form 2781: 2755: 2699: 2651: 2547: 2367: 2242: 1949: 1506: 1280: 1122: 924:), as a set of pairs ( 912:We define a ring over 876: 565:between MinSpec  282: 262: 4212:Lam (2005) p. 28 4178:Annals of Mathematics 3968:Lam (2005) p. 34 3893:Lam (2005) p. 32 3669:, and more generally 3398: 3339: 3293: 3267: 3247: 3223: 3165: 3113: 3065: 3022: 2989: 2850: 2812: 2782: 2756: 2700: 2652: 2548: 2368: 2243: 1950: 1559:corresponding to the 1507: 1281: 1123: 908:Rank and discriminant 877: 283: 263: 140:orthogonal direct sum 126:is the abelian group 4632:. pp. 539–579. 4403:Merkurjev, Alexander 4305:Tatra Mt. Math. Publ 4274:. pp. 365–387. 4121:Milnor, John Willard 3663:skew-symmetric forms 3437:quadratically closed 3368: 3302: 3276: 3256: 3236: 3174: 3122: 3074: 3034: 3001: 2866: 2821: 2791: 2765: 2717: 2698:{\displaystyle W(k)} 2680: 2563: 2447: 2439:split exact sequence 2289: 1960: 1644: 1523:) with its image in 1445: 1133: 963: 772: 272: 217: 3625:square-class groups 2228: 2206: 2099: 2077: 1305:. The elements of 1246: 1224: 702:The Witt ring of a 648:The Witt ring of a 530:with the orderings 304:a power of 2. The 204:Pythagorean closure 136:equivalence classes 4407:Serre, Jean-Pierre 4344:10.1007/bf02940871 4139:10.1007/BF01425486 3615:and the places of 3581:A¹ homotopy theory 3443:and the Witt ring 3425:Grothendieck group 3393: 3362:Vladimir Voevodsky 3334: 3288: 3262: 3242: 3218: 3160: 3108: 3060: 3017: 2984: 2845: 2807: 2777: 2751: 2705:form a descending 2695: 2647: 2622: 2543: 2512: 2363: 2335: 2238: 2207: 2185: 2078: 2056: 1945: 1502: 1276: 1225: 1203: 1118: 872: 438:nilpotent elements 385:correspond to the 371:ring homomorphisms 320:The Witt group of 278: 258: 114:Witt decomposition 4534:978-0-387-72487-4 4500:978-0-387-95385-4 4369:Conner, Pierre E. 3715:). The quadratic 3671:ε-quadratic forms 3468:, and indeed any 3375: 3265:{\displaystyle j} 3245:{\displaystyle i} 2997:is an element of 2855:is an element of 2646: 2607: 2542: 2497: 2359: 2326: 2234: 1331:Brauer–Wall group 1317:Brauer–Wall group 755:The Witt ring of 637:The Witt ring of 618:, and indeed any 614:The Witt ring of 588:Harrison topology 472:Pythagorean field 367:fundamental ideal 281:{\displaystyle w} 18:Witt ring (forms) 16:(Redirected from 4685: 4651: 4609: 4584: 4555:Husemoller, Dale 4546: 4519: 4478: 4436: 4394: 4356: 4355: 4327: 4321: 4320: 4300: 4294: 4293: 4263: 4257: 4250: 4244: 4237: 4231: 4228: 4222: 4219: 4213: 4210: 4204: 4203: 4194: 4164: 4158: 4157: 4117: 4111: 4110:Lam (2005) p.178 4108: 4102: 4101:Lam (2005) p.175 4099: 4093: 4092:Lam (2005) p.174 4090: 4084: 4083:Lam (2005) p.116 4081: 4075: 4072: 4066: 4063: 4057: 4054: 4048: 4045: 4039: 4038:Lam (2005) p.117 4036: 4030: 4029:Lam (2005) p.113 4027: 4021: 4018: 4012: 4011:Lam (2005) p.119 4009: 4003: 4002:Lam (2005) p.166 4000: 3994: 3993:Lam (2005) p.152 3991: 3978: 3975: 3969: 3966: 3951: 3950:Lam (2005) p.316 3948: 3942: 3939: 3933: 3930: 3924: 3921: 3915: 3912: 3903: 3900: 3894: 3891: 3885: 3882: 3873: 3870: 3859: 3856: 3847: 3844: 3838: 3835: 3829: 3826: 3817: 3814: 3805: 3802: 3796: 3793: 3787: 3784: 3587:Witt equivalence 3402: 3400: 3399: 3394: 3377: 3376: 3373: 3343: 3341: 3340: 3335: 3327: 3326: 3314: 3313: 3297: 3295: 3294: 3289: 3271: 3269: 3268: 3263: 3251: 3249: 3248: 3243: 3227: 3225: 3224: 3219: 3211: 3210: 3192: 3191: 3169: 3167: 3166: 3161: 3156: 3155: 3137: 3136: 3117: 3115: 3114: 3109: 3107: 3106: 3091: 3086: 3085: 3069: 3067: 3066: 3061: 3059: 3058: 3049: 3048: 3026: 3024: 3023: 3018: 3013: 3012: 2993: 2991: 2990: 2985: 2965: 2964: 2928: 2927: 2903: 2902: 2884: 2883: 2854: 2852: 2851: 2846: 2816: 2814: 2813: 2808: 2806: 2805: 2786: 2784: 2783: 2778: 2760: 2758: 2757: 2752: 2750: 2749: 2734: 2729: 2728: 2704: 2702: 2701: 2696: 2656: 2654: 2653: 2648: 2644: 2640: 2639: 2634: 2621: 2600: 2595: 2587: 2576: 2552: 2550: 2549: 2544: 2540: 2530: 2529: 2524: 2511: 2490: 2485: 2474: 2460: 2372: 2370: 2369: 2364: 2357: 2353: 2352: 2347: 2334: 2319: 2302: 2247: 2245: 2244: 2239: 2232: 2227: 2226: 2225: 2215: 2205: 2204: 2203: 2193: 2184: 2183: 2182: 2181: 2172: 2171: 2151: 2150: 2138: 2137: 2122: 2121: 2112: 2111: 2098: 2097: 2096: 2086: 2076: 2075: 2074: 2064: 2046: 2045: 2033: 2032: 2020: 2019: 2001: 2000: 1988: 1987: 1975: 1974: 1954: 1952: 1951: 1946: 1941: 1940: 1931: 1930: 1918: 1917: 1916: 1915: 1906: 1905: 1879: 1878: 1869: 1868: 1850: 1849: 1837: 1836: 1821: 1820: 1808: 1807: 1795: 1794: 1785: 1784: 1775: 1774: 1773: 1772: 1763: 1762: 1730: 1729: 1717: 1716: 1704: 1703: 1685: 1684: 1672: 1671: 1659: 1658: 1511: 1509: 1508: 1503: 1289:Then there is a 1285: 1283: 1282: 1277: 1269: 1268: 1259: 1258: 1245: 1244: 1243: 1233: 1223: 1222: 1221: 1211: 1193: 1192: 1180: 1179: 1161: 1160: 1148: 1147: 1127: 1125: 1124: 1119: 1114: 1113: 1101: 1100: 1088: 1087: 1078: 1077: 1068: 1067: 1066: 1065: 1056: 1055: 1023: 1022: 1010: 1009: 991: 990: 978: 977: 881: 879: 878: 873: 850: 849: 837: 836: 806: 786: 785: 780: 575:Zariski topology 326:commutative ring 287: 285: 284: 279: 267: 265: 264: 259: 172:torsion subgroup 106:hyperbolic plane 68:over the field. 32:algebraic groups 21: 4693: 4692: 4688: 4687: 4686: 4684: 4683: 4682: 4678:Quadratic forms 4668: 4667: 4658: 4640: 4630:Springer-Verlag 4628:. Vol. 2. 4619: 4616: 4614:Further reading 4587: 4573: 4563:Springer-Verlag 4549: 4535: 4522: 4501: 4481: 4459: 4439: 4425: 4399:Garibaldi, Skip 4397: 4383: 4367: 4364: 4359: 4329: 4328: 4324: 4302: 4301: 4297: 4282: 4265: 4264: 4260: 4251: 4247: 4242: 4238: 4234: 4229: 4225: 4220: 4216: 4211: 4207: 4172: 4166: 4165: 4161: 4119: 4118: 4114: 4109: 4105: 4100: 4096: 4091: 4087: 4082: 4078: 4073: 4069: 4064: 4060: 4055: 4051: 4046: 4042: 4037: 4033: 4028: 4024: 4019: 4015: 4010: 4006: 4001: 3997: 3992: 3981: 3977:Lam (2005) p.37 3976: 3972: 3967: 3954: 3949: 3945: 3940: 3936: 3931: 3927: 3922: 3918: 3913: 3906: 3901: 3897: 3892: 3888: 3883: 3876: 3871: 3862: 3857: 3850: 3845: 3841: 3836: 3832: 3827: 3820: 3815: 3808: 3803: 3799: 3794: 3790: 3785: 3781: 3777: 3765: 3736: 3725: 3710: 3667:quadratic forms 3659: 3653: 3651:Generalizations 3593:Witt equivalent 3589: 3578: 3566: 3497: 3461: 3409: 3366: 3365: 3318: 3305: 3300: 3299: 3274: 3273: 3254: 3253: 3234: 3233: 3202: 3183: 3172: 3171: 3147: 3128: 3120: 3119: 3092: 3077: 3072: 3071: 3050: 3040: 3032: 3031: 3004: 2999: 2998: 2956: 2919: 2894: 2875: 2864: 2863: 2819: 2818: 2797: 2789: 2788: 2763: 2762: 2735: 2720: 2715: 2714: 2678: 2677: 2666: 2629: 2561: 2560: 2519: 2445: 2444: 2437:We then have a 2433: 2430:= 2 we define ∂ 2425: 2412: 2406: 2393: 2384: 2342: 2287: 2286: 2276: 2217: 2195: 2173: 2163: 2152: 2142: 2129: 2113: 2103: 2088: 2066: 2037: 2024: 2011: 1992: 1979: 1966: 1958: 1957: 1932: 1922: 1907: 1897: 1892: 1870: 1860: 1841: 1828: 1812: 1799: 1786: 1776: 1764: 1754: 1749: 1721: 1708: 1695: 1676: 1663: 1650: 1642: 1641: 1561:Hilbert symbols 1553:Hasse invariant 1537: 1443: 1442: 1438:. This yields 1433: 1420: 1411: 1402: 1395: 1386: 1353:with valuation 1343: 1319: 1260: 1250: 1235: 1213: 1184: 1171: 1152: 1139: 1131: 1130: 1105: 1092: 1079: 1069: 1057: 1047: 1042: 1014: 1001: 982: 969: 961: 960: 910: 890: 841: 828: 775: 770: 769: 761: 747: 659: 611: 585: 535: 525: 450:Krull dimension 403:Noetherian ring 387:field orderings 324:can be given a 318: 270: 269: 215: 214: 74: 39: 28: 23: 22: 15: 12: 11: 5: 4691: 4689: 4681: 4680: 4670: 4669: 4666: 4665: 4657: 4656:External links 4654: 4653: 4652: 4638: 4615: 4612: 4611: 4610: 4585: 4571: 4547: 4533: 4520: 4499: 4479: 4457: 4441:Lam, Tsit-Yuen 4437: 4423: 4395: 4381: 4363: 4360: 4358: 4357: 4322: 4295: 4280: 4258: 4252:Fabien Morel, 4245: 4240: 4232: 4223: 4214: 4205: 4170: 4159: 4133:(4): 318–344, 4112: 4103: 4094: 4085: 4076: 4067: 4058: 4049: 4040: 4031: 4022: 4013: 4004: 3995: 3979: 3970: 3952: 3943: 3934: 3925: 3916: 3904: 3895: 3886: 3874: 3860: 3848: 3839: 3830: 3818: 3806: 3797: 3788: 3778: 3776: 3773: 3772: 3771: 3764: 3761: 3753:surgery theory 3734: 3723: 3705: 3655:Main article: 3652: 3649: 3635:) is called a 3623:between their 3588: 3585: 3576: 3565: 3562: 3561: 3560: 3537: 3522: 3499: 3495: 3481: 3460: 3457: 3449:exterior power 3408: 3405: 3392: 3389: 3386: 3383: 3380: 3333: 3330: 3325: 3321: 3317: 3312: 3308: 3287: 3284: 3281: 3261: 3241: 3217: 3214: 3209: 3205: 3201: 3198: 3195: 3190: 3186: 3182: 3179: 3159: 3154: 3150: 3146: 3143: 3140: 3135: 3131: 3127: 3105: 3102: 3099: 3095: 3090: 3084: 3080: 3057: 3053: 3047: 3043: 3039: 3016: 3011: 3007: 2995: 2994: 2983: 2980: 2977: 2974: 2971: 2968: 2963: 2959: 2955: 2952: 2949: 2946: 2943: 2940: 2937: 2934: 2931: 2926: 2922: 2918: 2915: 2912: 2909: 2906: 2901: 2897: 2893: 2890: 2887: 2882: 2878: 2874: 2871: 2844: 2841: 2838: 2835: 2832: 2829: 2826: 2804: 2800: 2796: 2776: 2773: 2770: 2748: 2745: 2742: 2738: 2733: 2727: 2723: 2694: 2691: 2688: 2685: 2665: 2662: 2658: 2657: 2643: 2638: 2633: 2628: 2625: 2620: 2617: 2614: 2610: 2606: 2603: 2599: 2594: 2590: 2586: 2582: 2579: 2575: 2571: 2568: 2554: 2553: 2539: 2536: 2533: 2528: 2523: 2518: 2515: 2510: 2507: 2504: 2500: 2496: 2493: 2489: 2484: 2480: 2477: 2473: 2469: 2466: 2463: 2459: 2455: 2452: 2431: 2421: 2408: 2402: 2389: 2380: 2374: 2373: 2362: 2356: 2351: 2346: 2341: 2338: 2333: 2329: 2325: 2322: 2318: 2314: 2311: 2308: 2305: 2301: 2297: 2294: 2275: 2272: 2249: 2248: 2237: 2231: 2224: 2220: 2214: 2210: 2202: 2198: 2192: 2188: 2180: 2176: 2170: 2166: 2162: 2159: 2155: 2149: 2145: 2141: 2136: 2132: 2128: 2125: 2120: 2116: 2110: 2106: 2102: 2095: 2091: 2085: 2081: 2073: 2069: 2063: 2059: 2055: 2052: 2049: 2044: 2040: 2036: 2031: 2027: 2023: 2018: 2014: 2010: 2007: 2004: 1999: 1995: 1991: 1986: 1982: 1978: 1973: 1969: 1965: 1955: 1944: 1939: 1935: 1929: 1925: 1921: 1914: 1910: 1904: 1900: 1895: 1891: 1888: 1885: 1882: 1877: 1873: 1867: 1863: 1859: 1856: 1853: 1848: 1844: 1840: 1835: 1831: 1827: 1824: 1819: 1815: 1811: 1806: 1802: 1798: 1793: 1789: 1783: 1779: 1771: 1767: 1761: 1757: 1752: 1748: 1745: 1742: 1739: 1736: 1733: 1728: 1724: 1720: 1715: 1711: 1707: 1702: 1698: 1694: 1691: 1688: 1683: 1679: 1675: 1670: 1666: 1662: 1657: 1653: 1649: 1594: ) with 1570:We define the 1536: 1533: 1513: 1512: 1501: 1498: 1495: 1492: 1489: 1486: 1483: 1480: 1477: 1474: 1471: 1468: 1465: 1462: 1459: 1456: 1453: 1450: 1429: 1416: 1407: 1400: 1391: 1384: 1349:be a complete 1342: 1339: 1318: 1315: 1287: 1286: 1275: 1272: 1267: 1263: 1257: 1253: 1249: 1242: 1238: 1232: 1228: 1220: 1216: 1210: 1206: 1202: 1199: 1196: 1191: 1187: 1183: 1178: 1174: 1170: 1167: 1164: 1159: 1155: 1151: 1146: 1142: 1138: 1128: 1117: 1112: 1108: 1104: 1099: 1095: 1091: 1086: 1082: 1076: 1072: 1064: 1060: 1054: 1050: 1045: 1041: 1038: 1035: 1032: 1029: 1026: 1021: 1017: 1013: 1008: 1004: 1000: 997: 994: 989: 985: 981: 976: 972: 968: 909: 906: 889: 886: 885: 884: 883: 882: 871: 868: 865: 862: 859: 856: 853: 848: 844: 840: 835: 831: 827: 824: 821: 818: 815: 812: 809: 805: 801: 798: 795: 792: 789: 784: 779: 764: 763: 759: 753: 745: 731: 700: 679:≡ 3 mod 4 and 655: 646: 635: 610: 607: 581: 545:MinSpec  533: 521: 407:square classes 317: 316:Ring structure 314: 277: 257: 254: 251: 248: 245: 242: 239: 236: 232: 229: 226: 222: 121:Witt group of 82:characteristic 73: 70: 66:bilinear forms 53:, named after 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4690: 4679: 4676: 4675: 4673: 4663: 4660: 4659: 4655: 4649: 4645: 4641: 4639:3-540-23019-X 4635: 4631: 4627: 4623: 4618: 4617: 4613: 4608: 4604: 4600: 4596: 4595: 4590: 4586: 4582: 4578: 4574: 4572:3-540-06009-X 4568: 4564: 4560: 4556: 4552: 4548: 4544: 4540: 4536: 4530: 4526: 4521: 4518: 4514: 4510: 4506: 4502: 4496: 4492: 4488: 4484: 4480: 4476: 4472: 4468: 4464: 4460: 4458:0-8218-1095-2 4454: 4450: 4446: 4442: 4438: 4434: 4430: 4426: 4424:0-8218-3287-5 4420: 4416: 4412: 4408: 4404: 4400: 4396: 4392: 4388: 4384: 4382:9971-966-05-0 4378: 4374: 4370: 4366: 4365: 4361: 4353: 4349: 4345: 4341: 4337: 4333: 4326: 4323: 4318: 4314: 4310: 4306: 4299: 4296: 4291: 4287: 4283: 4281:0-8218-5154-3 4277: 4273: 4269: 4262: 4259: 4255: 4249: 4246: 4236: 4233: 4227: 4224: 4218: 4215: 4209: 4206: 4202: 4198: 4193: 4188: 4184: 4180: 4179: 4174: 4163: 4160: 4156: 4152: 4148: 4144: 4140: 4136: 4132: 4128: 4127: 4122: 4116: 4113: 4107: 4104: 4098: 4095: 4089: 4086: 4080: 4077: 4071: 4068: 4062: 4059: 4053: 4050: 4044: 4041: 4035: 4032: 4026: 4023: 4017: 4014: 4008: 4005: 3999: 3996: 3990: 3988: 3986: 3984: 3980: 3974: 3971: 3965: 3963: 3961: 3959: 3957: 3953: 3947: 3944: 3938: 3935: 3929: 3926: 3920: 3917: 3911: 3909: 3905: 3899: 3896: 3890: 3887: 3881: 3879: 3875: 3869: 3867: 3865: 3861: 3855: 3853: 3849: 3843: 3840: 3834: 3831: 3825: 3823: 3819: 3813: 3811: 3807: 3801: 3798: 3792: 3789: 3783: 3780: 3774: 3770: 3767: 3766: 3762: 3760: 3758: 3754: 3750: 3746: 3744: 3740: 3733: 3729: 3722: 3718: 3714: 3709: 3704: 3700: 3696: 3692: 3689: 3687: 3681: 3679: 3676: 3672: 3668: 3664: 3658: 3650: 3648: 3646: 3642: 3638: 3634: 3630: 3626: 3622: 3618: 3614: 3610: 3606: 3602: 3596: 3594: 3586: 3584: 3582: 3574: 3573:perfect field 3570: 3563: 3558: 3554: 3550: 3546: 3544: 3538: 3535: 3531: 3527: 3523: 3520: 3516: 3512: 3508: 3504: 3500: 3494: 3490: 3486: 3482: 3479: 3475: 3471: 3467: 3463: 3462: 3458: 3456: 3454: 3450: 3446: 3442: 3438: 3434: 3430: 3426: 3422: 3417: 3414: 3406: 3404: 3390: 3387: 3381: 3363: 3358: 3356: 3351: 3347: 3331: 3328: 3323: 3319: 3315: 3310: 3306: 3285: 3282: 3279: 3259: 3239: 3231: 3207: 3203: 3199: 3196: 3193: 3188: 3184: 3152: 3148: 3144: 3141: 3138: 3133: 3129: 3103: 3100: 3097: 3093: 3088: 3082: 3078: 3055: 3045: 3041: 3029: 3014: 3009: 3005: 2975: 2969: 2961: 2957: 2947: 2938: 2932: 2924: 2920: 2910: 2899: 2895: 2891: 2888: 2885: 2880: 2876: 2862: 2861: 2860: 2858: 2839: 2833: 2827: 2802: 2798: 2794: 2771: 2746: 2743: 2740: 2736: 2731: 2725: 2721: 2712: 2708: 2689: 2683: 2675: 2671: 2661: 2636: 2623: 2618: 2615: 2612: 2608: 2604: 2601: 2597: 2588: 2580: 2566: 2559: 2558: 2557: 2537: 2526: 2513: 2508: 2505: 2502: 2498: 2494: 2491: 2487: 2464: 2450: 2443: 2442: 2441: 2440: 2435: 2429: 2424: 2420: 2416: 2411: 2405: 2401: 2397: 2392: 2388: 2383: 2379: 2360: 2349: 2336: 2331: 2327: 2323: 2309: 2292: 2285: 2284: 2283: 2281: 2273: 2271: 2268: 2266: 2262: 2258: 2254: 2235: 2222: 2218: 2212: 2208: 2200: 2196: 2190: 2186: 2178: 2174: 2168: 2164: 2160: 2157: 2147: 2143: 2139: 2134: 2130: 2123: 2118: 2114: 2108: 2104: 2100: 2093: 2089: 2083: 2079: 2071: 2067: 2061: 2057: 2050: 2042: 2038: 2034: 2029: 2025: 2021: 2016: 2012: 2005: 1997: 1993: 1989: 1984: 1980: 1976: 1971: 1967: 1956: 1937: 1933: 1927: 1923: 1912: 1908: 1902: 1898: 1889: 1886: 1880: 1875: 1871: 1865: 1861: 1857: 1846: 1842: 1838: 1833: 1829: 1822: 1817: 1813: 1809: 1804: 1800: 1796: 1791: 1787: 1781: 1777: 1769: 1765: 1759: 1755: 1746: 1743: 1734: 1726: 1722: 1718: 1713: 1709: 1705: 1700: 1696: 1689: 1681: 1677: 1673: 1668: 1664: 1660: 1655: 1651: 1640: 1639: 1638: 1635: 1634:just stated. 1633: 1629: 1625: 1621: 1617: 1613: 1609: 1605: 1601: 1597: 1593: 1589: 1585: 1581: 1577: 1573: 1568: 1566: 1562: 1558: 1555:±1 for every 1554: 1551:, there is a 1550: 1546: 1542: 1534: 1532: 1530: 1526: 1522: 1518: 1496: 1490: 1487: 1481: 1475: 1469: 1463: 1460: 1454: 1448: 1441: 1440: 1439: 1437: 1432: 1428: 1424: 1421:is a unit of 1419: 1415: 1410: 1406: 1399: 1394: 1390: 1383: 1379: 1375: 1371: 1367: 1364: 1360: 1356: 1352: 1348: 1340: 1338: 1336: 1332: 1328: 1324: 1316: 1314: 1312: 1308: 1304: 1300: 1296: 1292: 1273: 1265: 1261: 1255: 1251: 1247: 1240: 1236: 1230: 1226: 1218: 1214: 1208: 1204: 1197: 1189: 1185: 1181: 1176: 1172: 1165: 1157: 1153: 1149: 1144: 1140: 1129: 1110: 1106: 1102: 1097: 1093: 1089: 1084: 1080: 1074: 1070: 1062: 1058: 1052: 1048: 1039: 1036: 1027: 1019: 1015: 1011: 1006: 1002: 995: 987: 983: 979: 974: 970: 959: 958: 957: 955: 951: 947: 943: 939: 935: 931: 927: 923: 919: 915: 907: 905: 903: 899: 895: 887: 869: 863: 860: 857: 854: 851: 846: 842: 838: 833: 829: 825: 822: 819: 816: 813: 810: 803: 796: 793: 790: 782: 768: 767: 766: 765: 758: 754: 751: 744: 740: 736: 732: 729: 728:Klein 4-group 725: 721: 717: 713: 709: 708:maximal ideal 705: 701: 698: 694: 690: 686: 682: 678: 674: 670: 666: 663: 658: 654: 651: 647: 644: 640: 636: 633: 629: 625: 621: 617: 613: 612: 608: 606: 604: 603:Pfister forms 600: 596: 591: 589: 584: 580: 576: 572: 568: 564: 563:homeomorphism 560: 556: 552: 548: 544: 540: 536: 529: 524: 520: 516: 512: 508: 504: 500: 496: 492: 488: 483: 481: 477: 476:zero-divisors 473: 469: 464: 462: 458: 453: 451: 447: 443: 439: 435: 431: 426: 424: 420: 416: 412: 408: 404: 400: 399:Jacobson ring 396: 392: 388: 384: 380: 376: 372: 368: 364: 360: 355: 353: 348: 346: 342: 338: 335: 331: 327: 323: 315: 313: 311: 308:of the field 307: 303: 299: 295: 294:formally real 291: 275: 252: 249: 246: 243: 237: 227: 213: 212:Pfister forms 209: 205: 201: 197: 193: 189: 185: 181: 177: 173: 169: 164: 162: 158: 154: 150: 146: 141: 137: 133: 129: 125: 124: 117: 115: 111: 107: 103: 99: 95: 91: 87: 86:vector spaces 83: 79: 71: 69: 67: 64: 60: 59:abelian group 56: 52: 48: 44: 37: 33: 19: 4625: 4622:Handbook of 4621: 4601:(3): 31–44, 4598: 4592: 4558: 4551:Milnor, John 4527:. Springer. 4524: 4486: 4444: 4410: 4372: 4335: 4331: 4325: 4308: 4304: 4298: 4267: 4261: 4253: 4248: 4235: 4226: 4217: 4208: 4192:math/0101023 4182: 4176: 4168: 4162: 4130: 4124: 4115: 4106: 4097: 4088: 4079: 4070: 4061: 4052: 4043: 4034: 4025: 4016: 4007: 3998: 3973: 3946: 3937: 3928: 3919: 3898: 3889: 3842: 3833: 3800: 3791: 3782: 3748: 3747: 3742: 3738: 3731: 3727: 3720: 3716: 3712: 3707: 3702: 3698: 3694: 3690: 3685: 3682: 3677: 3660: 3644: 3640: 3636: 3632: 3628: 3620: 3616: 3612: 3608: 3604: 3600: 3597: 3592: 3590: 3569:Fabien Morel 3567: 3556: 3552: 3548: 3542: 3540: 3533: 3529: 3525: 3518: 3514: 3510: 3506: 3502: 3492: 3488: 3484: 3477: 3465: 3444: 3440: 3432: 3428: 3420: 3415: 3412: 3410: 3359: 3354: 3349: 2996: 2856: 2673: 2669: 2667: 2659: 2555: 2436: 2427: 2422: 2418: 2414: 2409: 2403: 2399: 2395: 2390: 2386: 2381: 2377: 2375: 2277: 2269: 2264: 2260: 2256: 2252: 2250: 1636: 1631: 1627: 1623: 1619: 1615: 1611: 1607: 1603: 1599: 1595: 1591: 1587: 1583: 1579: 1575: 1571: 1569: 1557:finite place 1548: 1545:number field 1540: 1538: 1528: 1524: 1520: 1516: 1515:identifying 1514: 1435: 1430: 1426: 1422: 1417: 1413: 1408: 1404: 1397: 1392: 1388: 1381: 1377: 1373: 1369: 1365: 1358: 1354: 1346: 1344: 1334: 1326: 1322: 1320: 1310: 1306: 1302: 1298: 1294: 1288: 953: 949: 945: 941: 937: 933: 929: 925: 921: 917: 913: 911: 902:Brauer group 894:discriminant 891: 756: 750:cyclic group 742: 738: 734: 723: 719: 715: 696: 692: 688: 676: 672: 668: 661: 656: 652: 650:finite field 642: 638: 631: 627: 615: 598: 594: 592: 582: 578: 570: 566: 558: 554: 550: 546: 538: 531: 522: 518: 514: 510: 506: 502: 498: 490: 486: 484: 479: 467: 465: 460: 456: 454: 441: 433: 429: 427: 422: 410: 393:, by taking 390: 382: 378: 374: 366: 362: 356: 351: 349: 345:Witt vectors 340: 336: 333: 321: 319: 309: 305: 289: 207: 199: 195: 191: 187: 183: 165: 161:homomorphism 156: 152: 148: 144: 131: 127: 122: 120: 118: 97: 77: 76:Fix a field 75: 46: 40: 27:Algebra term 4589:Witt, Ernst 4483:Lang, Serge 4338:: 175–185. 4185:(1): 1–13, 3673:, over any 3346:Milnor ring 3230:multilinear 3118:that sends 3028:John Milnor 2711:graded ring 1572:symbol ring 1425:with image 1351:local field 752:of order 2. 704:local field 573:) with the 401:. It is a 359:prime ideal 90:dimensional 43:mathematics 36:Witt vector 4662:Witt rings 4648:1115.19004 4607:0015.05701 4581:0292.10016 4543:1130.12001 4517:0984.00001 4475:1068.11023 4433:1159.12311 4391:0551.10017 4362:References 4352:0968.11038 4317:0978.11012 4290:0807.11024 3665:, and for 3579:(S) (see " 3272:such that 2707:filtration 1565:signatures 1291:surjective 888:Invariants 699:≡ 1 mod 4. 685:group ring 681:isomorphic 470:is a real 446:local ring 417:of finite 180:functorial 98:equivalent 72:Definition 55:Ernst Witt 47:Witt group 4147:0020-9910 3701:-groups 3283:≠ 3216:⟩ 3213:⟩ 3197:… 3181:⟨ 3178:⟨ 3142:… 3046:∗ 2979:⟩ 2973:⟨ 2970:− 2967:⟩ 2954:⟨ 2948:⋯ 2942:⟩ 2936:⟨ 2933:− 2930:⟩ 2917:⟨ 2908:⟩ 2905:⟩ 2889:… 2873:⟨ 2870:⟨ 2843:⟩ 2837:⟨ 2834:− 2831:⟩ 2825:⟨ 2775:⟩ 2769:⟨ 2616:≠ 2609:⨁ 2605:⊕ 2589:⊕ 2581:≅ 2535:→ 2506:≠ 2499:⨁ 2495:⊕ 2479:→ 2462:→ 2454:→ 2328:∏ 2324:⊕ 2307:→ 2259:) to Sym( 2006:⋅ 1887:− 1858:− 1744:− 1488:⋅ 1485:⟩ 1482:π 1479:⟨ 1476:⊕ 1363:injection 1329:) to the 1166:⋅ 1037:− 867:⟩ 861:− 808:⟨ 586:with the 528:bijection 503:signature 474:then the 395:signature 334:Witt ring 256:⟩ 250:− 241:⟨ 235:⟩ 231:⟩ 225:⟨ 221:⟨ 198:), where 182:map from 110:core form 63:symmetric 4672:Category 4557:(1973). 4485:(2002), 4443:(2005). 4409:(2003). 4311:: 7–16. 3763:See also 3657:L-theory 3517:⟩ where 3491:, where 3459:Examples 3298:one has 1412:⟩ where 928:,  741:) where 722:) where 609:Examples 543:spectrum 501:and the 448:and has 415:subgroup 302:exponent 57:, is an 4626:-theory 4509:1878556 4487:Algebra 4467:2104929 4155:0260844 3688:-groups 2426:) (for 1614:/2 and 932:) with 726:is the 683:to the 413:form a 369:. The 300:, with 298:torsion 292:is not 202:is the 178:of the 174:is the 4646:  4636:  4605:  4579:  4569:  4541:  4531:  4515:  4507:  4497:  4473:  4465:  4455:  4431:  4421:  4389:  4379:  4350:  4315:  4288:  4278:  4153:  4145:  3675:*-ring 3453:λ-ring 2761:. Let 2645:  2541:  2417:) → W( 2398:) → W( 2385:) → W( 2358:  2233:  1578:, Sym( 1396:⟩ to ⟨ 601:-fold 306:height 176:kernel 34:, see 4187:arXiv 3775:Notes 3639:or a 3476:, is 1574:over 1543:be a 748:is a 706:with 695:) if 660:with 626:, is 553:) of 513:) to 493:then 444:is a 419:index 381:) to 373:from 268:with 190:) to 168:order 159:is a 134:) of 112:of a 51:field 49:of a 4634:ISBN 4567:ISBN 4529:ISBN 4495:ISBN 4453:ISBN 4419:ISBN 4377:ISBN 4276:ISBN 4143:ISSN 3603:and 3583:"). 3411:The 3374:char 3252:and 2668:Let 2413:: W( 2278:The 1539:Let 1403:,... 1387:,... 1372:) → 1345:Let 944:and 712:norm 593:The 151:) → 119:The 96:are 45:, a 4644:Zbl 4603:Zbl 4599:176 4577:Zbl 4539:Zbl 4513:Zbl 4471:Zbl 4429:Zbl 4387:Zbl 4348:Zbl 4340:doi 4313:Zbl 4286:Zbl 4197:doi 4183:165 4135:doi 3577:0,0 3528:⊕ ( 3472:or 3348:of 3228:is 3170:to 3070:to 1610:in 1598:in 1531:). 1434:in 1337:). 1333:BW( 948:in 936:in 710:of 675:if 667:is 665:odd 641:is 622:or 537:of 485:If 478:of 466:If 455:If 452:0. 428:If 389:of 206:of 80:of 41:In 4674:: 4642:. 4597:, 4575:. 4565:. 4553:; 4537:. 4511:, 4505:MR 4503:, 4489:, 4469:. 4463:MR 4461:. 4447:. 4427:. 4417:. 4405:; 4401:; 4385:. 4346:. 4336:69 4334:. 4309:11 4307:. 4284:. 4195:, 4181:, 4173:/2 4151:MR 4149:, 4141:, 4129:, 3982:^ 3955:^ 3907:^ 3877:^ 3863:^ 3851:^ 3821:^ 3809:^ 3759:. 3680:. 3631:, 3555:/2 3551:⊕ 3547:/4 3543:⊕ 3541:Z' 3536:). 3532:/2 3509:/2 3505:⊕ 3455:. 3441:GW 3431:→ 3429:GW 3421:GW 3416:GW 2267:. 1606:, 1604:K* 1600:K* 1590:, 1586:, 1313:. 952:/2 942:K* 938:K* 916:, 737:/4 718:/2 691:/2 671:/4 630:/2 605:. 590:. 440:; 425:. 361:, 347:. 163:. 155:/2 116:. 4650:. 4624:K 4583:. 4545:. 4477:. 4435:. 4393:. 4354:. 4342:: 4319:. 4292:. 4254:A 4241:0 4199:: 4189:: 4171:* 4169:K 4137:: 4131:9 3749:L 3743:L 3739:R 3737:( 3735:2 3732:L 3728:R 3726:( 3724:0 3721:L 3717:L 3713:R 3711:( 3708:k 3706:2 3703:L 3699:L 3695:R 3693:( 3691:L 3686:L 3678:R 3645:l 3633:t 3629:T 3621:t 3617:L 3613:K 3609:T 3605:L 3601:K 3559:. 3557:Z 3553:Z 3549:Z 3545:Z 3534:Z 3530:Z 3526:Z 3519:a 3515:a 3511:Z 3507:Z 3503:Z 3496:2 3493:C 3489:Z 3485:R 3480:. 3478:Z 3466:C 3445:W 3433:Z 3391:0 3388:= 3385:) 3382:k 3379:( 3355:k 3350:k 3332:1 3329:= 3324:j 3320:a 3316:+ 3311:i 3307:a 3286:j 3280:i 3260:j 3240:i 3208:n 3204:a 3200:, 3194:, 3189:1 3185:a 3158:) 3153:n 3149:a 3145:, 3139:, 3134:1 3130:a 3126:( 3104:1 3101:+ 3098:n 3094:I 3089:/ 3083:n 3079:I 3056:n 3052:) 3042:k 3038:( 3015:. 3010:n 3006:I 2982:) 2976:1 2962:n 2958:a 2951:( 2945:) 2939:1 2925:1 2921:a 2914:( 2911:= 2900:n 2896:a 2892:, 2886:, 2881:1 2877:a 2857:I 2840:1 2828:a 2803:2 2799:x 2795:a 2772:a 2747:1 2744:+ 2741:n 2737:I 2732:/ 2726:n 2722:I 2693:) 2690:k 2687:( 2684:W 2674:I 2670:k 2642:) 2637:p 2632:F 2627:( 2624:W 2619:2 2613:p 2602:2 2598:/ 2593:Z 2585:Z 2578:) 2574:Q 2570:( 2567:W 2538:0 2532:) 2527:p 2522:F 2517:( 2514:W 2509:2 2503:p 2492:2 2488:/ 2483:Z 2476:) 2472:Q 2468:( 2465:W 2458:Z 2451:0 2432:2 2428:p 2423:p 2419:F 2415:Q 2410:p 2404:p 2400:Q 2396:Q 2391:p 2387:F 2382:p 2378:Q 2361:. 2355:) 2350:p 2345:Q 2340:( 2337:W 2332:p 2321:) 2317:R 2313:( 2310:W 2304:) 2300:Q 2296:( 2293:W 2265:I 2261:K 2257:K 2255:( 2253:W 2236:. 2230:) 2223:1 2219:e 2213:2 2209:f 2201:2 2197:e 2191:1 2187:f 2179:2 2175:e 2169:1 2165:e 2161:+ 2158:1 2154:] 2148:2 2144:d 2140:, 2135:1 2131:d 2127:[ 2124:, 2119:2 2115:e 2109:1 2105:e 2101:, 2094:1 2090:e 2084:2 2080:d 2072:2 2068:e 2062:1 2058:d 2054:( 2051:= 2048:) 2043:2 2039:f 2035:, 2030:2 2026:e 2022:, 2017:2 2013:d 2009:( 2003:) 1998:1 1994:f 1990:, 1985:1 1981:e 1977:, 1972:1 1968:d 1964:( 1943:) 1938:2 1934:f 1928:1 1924:f 1920:] 1913:2 1909:e 1903:1 1899:e 1894:) 1890:1 1884:( 1881:, 1876:2 1872:d 1866:1 1862:d 1855:[ 1852:] 1847:2 1843:d 1839:, 1834:1 1830:d 1826:[ 1823:, 1818:2 1814:e 1810:+ 1805:1 1801:e 1797:, 1792:2 1788:d 1782:1 1778:d 1770:2 1766:e 1760:1 1756:e 1751:) 1747:1 1741:( 1738:( 1735:= 1732:) 1727:2 1723:f 1719:, 1714:2 1710:e 1706:, 1701:2 1697:d 1693:( 1690:+ 1687:) 1682:1 1678:f 1674:, 1669:1 1665:e 1661:, 1656:1 1652:d 1648:( 1632:f 1628:f 1624:f 1620:K 1616:f 1612:Z 1608:e 1602:/ 1596:d 1592:f 1588:e 1584:d 1580:K 1576:K 1549:K 1541:K 1529:K 1527:( 1525:W 1521:k 1519:( 1517:W 1500:) 1497:k 1494:( 1491:W 1473:) 1470:k 1467:( 1464:W 1461:= 1458:) 1455:K 1452:( 1449:W 1436:k 1431:i 1427:a 1423:K 1418:i 1414:u 1409:n 1405:u 1401:1 1398:u 1393:n 1389:a 1385:1 1382:a 1378:K 1376:( 1374:W 1370:k 1368:( 1366:W 1359:k 1355:v 1347:K 1335:K 1327:K 1325:( 1323:W 1311:K 1307:Q 1303:I 1299:K 1297:( 1295:W 1274:. 1271:) 1266:2 1262:e 1256:1 1252:e 1248:, 1241:1 1237:e 1231:2 1227:d 1219:2 1215:e 1209:1 1205:d 1201:( 1198:= 1195:) 1190:2 1186:e 1182:, 1177:2 1173:d 1169:( 1163:) 1158:1 1154:e 1150:, 1145:1 1141:d 1137:( 1116:) 1111:2 1107:e 1103:+ 1098:1 1094:e 1090:, 1085:2 1081:d 1075:1 1071:d 1063:2 1059:e 1053:1 1049:e 1044:) 1040:1 1034:( 1031:( 1028:= 1025:) 1020:2 1016:e 1012:, 1007:2 1003:d 999:( 996:+ 993:) 988:1 984:e 980:, 975:1 971:d 967:( 954:Z 950:Z 946:e 940:/ 934:d 930:e 926:d 922:K 920:( 918:Q 914:K 870:. 864:4 858:t 855:s 852:, 847:2 843:t 839:, 834:2 830:s 826:, 823:t 820:2 817:, 814:s 811:2 804:/ 800:] 797:t 794:, 791:s 788:[ 783:8 778:Z 760:2 757:Q 746:2 743:C 739:Z 735:Z 730:. 724:V 720:Z 716:Z 697:q 693:Z 689:Z 687:( 677:q 673:Z 669:Z 662:q 657:q 653:F 645:. 643:Z 639:R 634:. 632:Z 628:Z 616:C 599:n 595:n 583:k 579:X 571:k 569:( 567:W 559:k 557:( 555:W 551:k 549:( 547:W 539:k 534:k 532:X 523:P 519:K 515:Z 511:k 509:( 507:W 499:k 491:P 487:k 480:W 468:k 461:W 457:k 442:W 434:W 430:k 423:k 411:k 391:k 383:Z 379:k 377:( 375:W 363:I 352:k 341:k 339:( 337:W 322:k 310:k 290:k 276:w 253:w 247:, 244:1 238:= 228:w 208:k 200:k 196:k 194:( 192:W 188:k 186:( 184:W 157:Z 153:Z 149:k 147:( 145:W 132:k 130:( 128:W 123:k 78:k 38:. 20:)

Index

Witt ring (forms)
algebraic groups
Witt vector
mathematics
field
Ernst Witt
abelian group
symmetric
bilinear forms
characteristic
vector spaces
dimensional
symmetric bilinear forms
metabolic quadratic space
hyperbolic plane
core form
Witt decomposition
equivalence classes
orthogonal direct sum
homomorphism
order
torsion subgroup
kernel
functorial
Pythagorean closure
Pfister forms
formally real
torsion
exponent
commutative ring

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