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Analytic function

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Real and complex analytic functions have important differences (one could notice that even from their different relationship with differentiability). Analyticity of complex functions is a more restrictive property, as it has more restrictive necessary conditions and complex analytic functions have
2452:, that is, infinitely differentiable. The converse is not true for real functions; in fact, in a certain sense, the real analytic functions are sparse compared to all real infinitely differentiable functions. For the complex numbers, the converse does hold, and in fact any function differentiable 2588:
A polynomial cannot be zero at too many points unless it is the zero polynomial (more precisely, the number of zeros is at most the degree of the polynomial). A similar but weaker statement holds for analytic functions. If the set of zeros of an analytic function ƒ has an
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on the real line can be extended to a complex analytic function on some open set of the complex plane. However, not every real analytic function defined on the whole real line can be extended to a complex function defined on the whole complex plane. The function
796: 2910:). Analytic functions of several variables have some of the same properties as analytic functions of one variable. However, especially for complex analytic functions, new and interesting phenomena show up in 2 or more complex dimensions: 2928:
for single-valued functions consist of arbitrary (connected) open sets. In several complex variables, however, only some connected open sets are domains of holomorphy. The characterization of domains of holomorphy leads to the notion of
2739:, any bounded complex analytic function defined on the whole complex plane is constant. The corresponding statement for real analytic functions, with the complex plane replaced by the real line, is clearly false; this is illustrated by 1098: 2031: 1667: 2299: 2291: 609: 2488: 1241: 2800: 1273: 2526: 2083: 2696: 1799: 2570: 2202: 2117: 845: 1696: 1580: 1551: 2228: 328: 2698:). (Note that this differentiability is in the sense of real variables; compare complex derivatives below.) There exist smooth real functions that are not analytic: see 1870: 601: 1524:* is not complex analytic, although its restriction to the real line is the identity function and therefore real analytic, and it is real analytic as a function from 1916: 3016: 1385:
is obtained by replacing, in the definitions above, "real" with "complex" and "real line" with "complex plane". A function is complex analytic if and only if it is
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with respect to the uniform convergence on compact sets. The fact that uniform limits on compact sets of analytic functions are analytic is an easy consequence of
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in its Taylor series expansion must immediately vanish to 0, and so this series will be trivially convergent. Furthermore, every polynomial is its own
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Also, if all the derivatives of an analytic function at a point are zero, the function is constant on the corresponding connected component.
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i.e. it is complex differentiable. For this reason the terms "holomorphic" and "analytic" are often used interchangeably for such functions.
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The situation is quite different when one considers complex analytic functions and complex derivatives. It can be proved that
2410:{\displaystyle \sup _{x\in K}\left|{\frac {\partial ^{\alpha }f}{\partial x^{\alpha }}}(x)\right|\leq C^{|\alpha |+1}\alpha !} 2043:
For the case of an analytic function with several variables (see below), the real analyticity can be characterized using the
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at distance 1 from the evaluation point 0 and no further poles within the open disc of radius 1 around the evaluation point.
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This article is about both real and complex analytic functions. For analytic functions in complex analysis specifically, see
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functions (functions given by different formulae in different regions) are typically not analytic where the pieces meet.
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In the multivariable case, real analytic functions satisfy a direct generalization of the third characterization. Let
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of an analytic function that is nowhere zero is analytic, as is the inverse of an invertible analytic function whose
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As noted above, any analytic function (real or complex) is infinitely differentiable (also known as smooth, or
2497: 2053: 2670: 372:, but complex analytic functions exhibit properties that do not generally hold for real analytic functions. 2958: 1473: 407: 1776: 3340:
Solver for all zeros of a complex analytic function that lie within a rectangular region by Ivan B. Ivanov
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One can define analytic functions in several variables by means of power series in those variables (see
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of the complex plane) is not true in general; the function of the example above gives an example for
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of order 1. So just having a polynomial expansion at singular points is not enough, and the
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on an open set is analytic on that set (see "analyticity and differentiability" below).
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any complex function differentiable (in the complex sense) in an open set is analytic
2577: 939: 473: 469: 376: 219: 214: 103: 2907: 2895: 2581: 1093:{\displaystyle T(x)=\sum _{n=0}^{\infty }{\frac {f^{(n)}(x_{0})}{n!}}(x-x_{0})^{n}} 357: 3164: 1844: 342: 274: 93: 2874:) defined in the paragraph above is a counterexample, as it is not defined for 1298:
defined on some subset of the real line is said to be real analytic at a point
441:. It is important to note that it is a neighborhood and not just at some point 2827:). This statement for real analytic functions (with open ball meaning an open 2438: 1409: 3190: 3181: 2842: = 0 and a ball of radius exceeding 1, since the power series 3330: 3137: 2914:
Zero sets of complex analytic functions in more than one variable are never
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is analytic. Any Taylor series for this function converges not only for
2026:{\displaystyle \left|{\frac {d^{k}f}{dx^{k}}}(x)\right|\leq C^{k+1}k!} 1662:{\displaystyle f\in {\mathcal {C}}_{0}^{\infty }(\mathbb {R} ^{n})} 503:
to be considered an analytic function. As a counterexample see the
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These statements imply that while analytic functions do have more
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is not everywhere analytic because it is not differentiable at 0.
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Also, if a complex analytic function is defined in an open
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must also converge to the function on points adjacent to
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Typical examples of functions that are not analytic are
1182:. The set of all real analytic functions on a given set 2601:
containing the accumulation point. In other words, if (
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A guide to distribution theory and Fourier transforms
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Complex analytic functions are exactly equivalent to
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is also used in the literature do denote analyticity
2286:{\displaystyle \alpha \in \mathbb {Z} _{\geq 0}^{n}} 1499:
function when defined on the set of real numbers or
3035: 3010: 2794: 2732:more structure than their real-line counterparts. 2690: 2564: 2520: 2482: 2409: 2285: 2242: 2222: 2196: 2154: 2134: 2111: 2077: 2025: 1930: 1910: 1884: 1864: 1835: 1813: 1793: 1765: 1742: 1722: 1690: 1661: 1601: 1574: 1545: 1370: 1350: 1330: 1310: 1290: 1267: 1235: 1194: 1171: 1144: 1124: 1092: 961: 923: 896: 876: 839: 790: 595: 558: 531: 495: 460: 429: 398: 2991:as well in a (possibly smaller) neighborhood of 2304: 3165:"A characterization of real analytic functions" 2040:, and are thus much more easily characterized. 1470:(at least in some range of the complex plane): 2659:than polynomials, they are still quite rigid. 934:Alternatively, a real analytic function is an 2894:is 1 because the complexified function has a 2483:{\displaystyle \Omega \subseteq \mathbb {C} } 1461:are analytic on any open set of their domain. 1442:(as in the definition) but for all values of 1236:{\displaystyle {\mathcal {C}}^{\,\omega }(D)} 322: 8: 3205:"Gevrey class - Encyclopedia of Mathematics" 3227: 3150: 2964:Infinite compositions of analytic functions 2882:. This explains why the Taylor series of ƒ( 1397:Typical examples of analytic functions are 2795:{\displaystyle f(x)={\frac {1}{x^{2}+1}}.} 1268:{\displaystyle {\mathcal {C}}^{\,\omega }} 375:A function is analytic if and only if its 329: 315: 51: 3180: 3002: 2996: 2774: 2764: 2747: 2702:. In fact there are many such functions. 2682: 2676: 2675: 2672: 2547: 2541: 2521:{\displaystyle u:\Omega \to \mathbb {C} } 2514: 2513: 2499: 2476: 2475: 2467: 2388: 2380: 2379: 2349: 2331: 2324: 2307: 2301: 2277: 2269: 2265: 2264: 2255: 2235: 2209: 2179: 2167: 2147: 2127: 2105: 2104: 2090: 2078:{\displaystyle U\subset \mathbb {R} ^{n}} 2069: 2065: 2064: 2055: 2005: 1975: 1957: 1950: 1943: 1923: 1897: 1877: 1851: 1828: 1806: 1787: 1786: 1778: 1758: 1753:There is a complex analytic extension of 1735: 1715: 1707:The following conditions are equivalent: 1682: 1678: 1677: 1674: 1650: 1646: 1645: 1635: 1630: 1624: 1623: 1614: 1594: 1566: 1562: 1561: 1558: 1537: 1533: 1532: 1529: 1363: 1343: 1323: 1303: 1283: 1259: 1258: 1252: 1251: 1248: 1218: 1217: 1211: 1210: 1207: 1187: 1163: 1157: 1137: 1108: 1084: 1074: 1041: 1022: 1015: 1009: 998: 977: 953: 947: 915: 909: 889: 860: 825: 812: 806: 776: 766: 747: 731: 712: 699: 686: 675: 653: 643: 632: 611: 581: 575: 551: 524: 487: 481: 452: 446: 421: 415: 390: 384: 2691:{\displaystyle {\mathcal {C}}^{\infty }} 1589:, and in particular any smooth function 3026: 2980: 2902:Analytic functions of several variables 244: 237: 159: 121: 83: 67: 2823:is convergent in the whole open ball ( 2727:Real versus complex analytic functions 3077:if its derivative exists not only at 2831:of the real line rather than an open 1794:{\displaystyle G\subset \mathbb {C} } 45:. For analytic functions in SQL, see 7: 3255:11 (2nd ed.). Springer-Verlag. 3096:if it is analytic at every point in 2565:{\displaystyle A_{\infty }(\Omega )} 3279:A Primer of Real Analytic Functions 3249:Functions of One Complex Variable I 2865:Any real analytic function on some 2597:, then ƒ is zero everywhere on the 2430:of analytic functions are analytic. 2197:{\displaystyle f\in C^{\infty }(U)} 2112:{\displaystyle f:U\to \mathbb {R} } 3038:Complex Variables and Applications 2825:holomorphic functions are analytic 2683: 2556: 2548: 2507: 2469: 2342: 2328: 2180: 2045:Fourier–Bros–Iagolnitzer transform 1636: 1416:, any terms of degree larger than 1010: 936:infinitely differentiable function 840:{\displaystyle a_{0},a_{1},\dots } 644: 406:converges to the function in some 25: 3034:Churchill; Brown; Verhey (1948). 2663:Analyticity and differentiability 3169:Proceedings of the Japan Academy 2816:, its power series expansion at 2612:of distinct numbers such that ƒ( 2421:Properties of analytic functions 2250:such that for every multi-index 1730:is real analytic on an open set 1691:{\displaystyle \mathbb {R} ^{n}} 1575:{\displaystyle \mathbb {R} ^{2}} 1546:{\displaystyle \mathbb {R} ^{2}} 296: 75: 2494:(Ω) of all analytic functions 2441:is nowhere zero. (See also the 1918:and every non-negative integer 27:Type of function in mathematics 3116:Strichartz, Robert S. (1994). 2890:| > 1, i.e., the 2758: 2752: 2559: 2553: 2510: 2389: 2381: 2364: 2358: 2191: 2185: 2101: 1990: 1984: 1656: 1641: 1230: 1224: 1119: 1113: 1081: 1061: 1047: 1034: 1029: 1023: 988: 982: 871: 865: 773: 753: 737: 718: 622: 616: 1: 3253:Graduate Texts in Mathematics 3092:. It is analytic in a region 1703:Alternative characterizations 1587:non-analytic smooth functions 1412:: if a polynomial has degree 1275:if the domain is understood. 368:. Functions of each type are 3281:(2nd ed.). BirkhĂ€user. 3163:Komatsu, Hikosaburo (1960). 2969:Non-analytic smooth function 2700:non-analytic smooth function 2576:analytic functions with the 2223:{\displaystyle K\subseteq U} 3309:Encyclopedia of Mathematics 2920:Hartogs's extension theorem 1609:with compact support, i.e. 1318:if there is a neighborhood 353:that is locally given by a 3371: 2443:Lagrange inversion theorem 2293:the following bound holds 1938:the following bound holds 1865:{\displaystyle K\subset D} 801:in which the coefficients 596:{\displaystyle x_{0}\in D} 366:complex analytic functions 40: 29: 3122:. Boca Raton: CRC Press. 2448:Any analytic function is 1383:complex analytic function 847:are real numbers and the 370:infinitely differentiable 239:Geometric function theory 185:Cauchy's integral formula 175:Cauchy's integral theorem 3085:in some neighborhood of 3062:of the complex variable 2944:Cauchy–Riemann equations 2918:. This can be proved by 2621:) = 0 for all 2426:The sums, products, and 2230:there exists a constant 2085:be an open set, and let 1872:there exists a constant 1843:is smooth and for every 1669:, cannot be analytic on 1474:hypergeometric functions 147:Cauchy–Riemann equations 30:Not to be confused with 3228:Krantz & Parks 2002 3151:Krantz & Parks 2002 3042:. McGraw-Hill. p.  2959:Quasi-analytic function 2645:. This is known as the 1451:trigonometric functions 362:real analytic functions 132:Complex-valued function 3209:encyclopediaofmath.org 3182:10.3792/pja/1195524081 3012: 2796: 2692: 2566: 2522: 2484: 2411: 2287: 2244: 2224: 2204:and for every compact 2198: 2156: 2136: 2113: 2079: 2027: 1932: 1912: 1911:{\displaystyle x\in K} 1886: 1866: 1837: 1815: 1795: 1767: 1744: 1724: 1692: 1663: 1603: 1576: 1547: 1372: 1352: 1332: 1312: 1292: 1269: 1237: 1196: 1173: 1146: 1126: 1094: 1014: 963: 925: 898: 878: 841: 792: 648: 597: 560: 533: 497: 462: 431: 400: 303:Mathematics portal 18:Real analytic function 3013: 3011:{\displaystyle x_{0}} 2926:Domains of holomorphy 2892:radius of convergence 2797: 2693: 2567: 2523: 2485: 2412: 2288: 2245: 2225: 2199: 2157: 2137: 2114: 2080: 2038:holomorphic functions 2028: 1933: 1913: 1887: 1867: 1838: 1816: 1796: 1768: 1745: 1725: 1693: 1664: 1604: 1577: 1548: 1373: 1353: 1333: 1313: 1293: 1270: 1238: 1197: 1174: 1172:{\displaystyle x_{0}} 1152:in a neighborhood of 1147: 1127: 1095: 994: 964: 962:{\displaystyle x_{0}} 926: 924:{\displaystyle x_{0}} 904:in a neighborhood of 899: 879: 842: 793: 628: 598: 561: 534: 519:Formally, a function 498: 496:{\displaystyle x_{0}} 463: 461:{\displaystyle x_{0}} 432: 430:{\displaystyle x_{0}} 401: 399:{\displaystyle x_{0}} 255:Augustin-Louis Cauchy 57:Mathematical analysis 47:Window function (SQL) 2995: 2954:Paley–Wiener theorem 2949:Holomorphic function 2746: 2720:holomorphic function 2671: 2540: 2498: 2466: 2300: 2254: 2234: 2208: 2166: 2146: 2142:is real analytic on 2126: 2089: 2054: 1942: 1922: 1896: 1892:such that for every 1876: 1850: 1827: 1805: 1777: 1757: 1734: 1714: 1673: 1613: 1593: 1557: 1528: 1429:exponential function 1403:elementary functions 1381:The definition of a 1362: 1342: 1322: 1302: 1282: 1247: 1206: 1202:is often denoted by 1186: 1156: 1136: 1125:{\displaystyle f(x)} 1107: 976: 946: 908: 888: 877:{\displaystyle f(x)} 859: 805: 610: 574: 550: 523: 505:Weierstrass function 480: 445: 414: 383: 265:Carl Friedrich Gauss 200:Isolated singularity 142:Holomorphic function 43:holomorphic function 3326:"Analytic Function" 3304:"Analytic function" 2989:uniform convergence 2737:Liouville's theorem 2717:is synonymous with 2709:. Consequently, in 2599:connected component 2282: 1640: 360:. There exist both 152:Formal power series 114:Unit complex number 32:analytic expression 3355:Analytic functions 3323:Weisstein, Eric W. 3081:but at each point 3008: 2792: 2688: 2657:degrees of freedom 2625:and this sequence 2591:accumulation point 2562: 2518: 2480: 2407: 2318: 2283: 2263: 2240: 2220: 2194: 2152: 2132: 2109: 2075: 2023: 1928: 1908: 1882: 1862: 1833: 1811: 1791: 1763: 1740: 1720: 1688: 1659: 1622: 1599: 1572: 1543: 1446:(real or complex). 1378:is real analytic. 1368: 1348: 1328: 1308: 1288: 1265: 1233: 1192: 1169: 1142: 1122: 1090: 959: 921: 894: 874: 837: 788: 593: 556: 529: 493: 458: 427: 396: 230:Laplace's equation 210:Argument principle 3262:978-0-387-90328-6 2862:| â‰„ 1. 2787: 2715:analytic function 2633:in the domain of 2356: 2303: 2243:{\displaystyle C} 2155:{\displaystyle U} 2135:{\displaystyle f} 1982: 1931:{\displaystyle k} 1885:{\displaystyle C} 1836:{\displaystyle f} 1814:{\displaystyle D} 1766:{\displaystyle f} 1743:{\displaystyle D} 1723:{\displaystyle f} 1602:{\displaystyle f} 1514:complex conjugate 1507:Piecewise defined 1468:special functions 1371:{\displaystyle f} 1351:{\displaystyle x} 1331:{\displaystyle D} 1311:{\displaystyle x} 1291:{\displaystyle f} 1195:{\displaystyle D} 1145:{\displaystyle x} 1059: 897:{\displaystyle x} 559:{\displaystyle D} 532:{\displaystyle f} 347:analytic function 339: 338: 225:Harmonic function 137:Analytic function 123:Complex functions 109:Complex conjugate 16:(Redirected from 3362: 3336: 3335: 3317: 3292: 3275:Parks, Harold R. 3266: 3231: 3225: 3219: 3218: 3216: 3215: 3201: 3195: 3194: 3184: 3160: 3154: 3148: 3142: 3141: 3113: 3107: 3106: 3041: 3031: 3019: 3017: 3015: 3014: 3009: 3007: 3006: 2985: 2886:) diverges for | 2857: 2801: 2799: 2798: 2793: 2788: 2786: 2779: 2778: 2765: 2711:complex analysis 2697: 2695: 2694: 2689: 2687: 2686: 2681: 2680: 2647:identity theorem 2571: 2569: 2568: 2563: 2552: 2551: 2534:Morera's theorem 2527: 2525: 2524: 2519: 2517: 2489: 2487: 2486: 2481: 2479: 2416: 2414: 2413: 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61:Complex analysis 52: 21: 3370: 3369: 3365: 3364: 3363: 3361: 3360: 3359: 3345: 3344: 3321: 3320: 3302: 3299: 3289: 3269: 3263: 3245:Conway, John B. 3243: 3240: 3235: 3234: 3226: 3222: 3213: 3211: 3203: 3202: 3198: 3162: 3161: 3157: 3149: 3145: 3130: 3115: 3114: 3110: 3091: 3076: 3054: 3033: 3032: 3028: 3023: 3022: 2998: 2993: 2992: 2986: 2982: 2977: 2940: 2931:pseudoconvexity 2904: 2843: 2841: 2822: 2815: 2809:around a point 2770: 2769: 2744: 2743: 2729: 2674: 2669: 2668: 2665: 2620: 2606: 2543: 2538: 2537: 2496: 2495: 2464: 2463: 2423: 2375: 2345: 2341: 2327: 2326: 2323: 2319: 2298: 2297: 2252: 2251: 2232: 2231: 2206: 2205: 2175: 2164: 2163: 2162:if and only if 2144: 2143: 2124: 2123: 2087: 2086: 2063: 2052: 2051: 2001: 1971: 1967: 1953: 1952: 1949: 1945: 1940: 1939: 1920: 1919: 1894: 1893: 1874: 1873: 1848: 1847: 1825: 1824: 1803: 1802: 1801:which contains 1775: 1774: 1773:to an open set 1755: 1754: 1732: 1731: 1712: 1711: 1705: 1676: 1671: 1670: 1644: 1611: 1610: 1591: 1590: 1560: 1555: 1554: 1531: 1526: 1525: 1501:complex numbers 1484:gamma functions 1459:power functions 1441: 1395: 1360: 1359: 1340: 1339: 1320: 1319: 1300: 1299: 1280: 1279: 1250: 1245: 1244: 1209: 1204: 1203: 1184: 1183: 1159: 1154: 1153: 1134: 1133: 1105: 1104: 1080: 1070: 1051: 1037: 1018: 1017: 974: 973: 949: 944: 943: 911: 906: 905: 886: 885: 857: 856: 821: 808: 803: 802: 772: 762: 743: 727: 708: 695: 671: 664: 660: 659: 649: 608: 607: 603:one can write 577: 572: 571: 548: 547: 521: 520: 517: 509:Fabius function 483: 478: 477: 448: 443: 442: 417: 412: 411: 386: 381: 380: 335: 295: 205:Residue theorem 180:Local primitive 170:Zeros and poles 85:Complex numbers 55: 50: 39: 36:analytic signal 28: 23: 22: 15: 12: 11: 5: 3368: 3366: 3358: 3357: 3347: 3346: 3343: 3342: 3337: 3318: 3298: 3297:External links 3295: 3294: 3293: 3287: 3271:Krantz, Steven 3267: 3261: 3239: 3236: 3233: 3232: 3220: 3196: 3155: 3143: 3128: 3108: 3089: 3074: 3052: 3025: 3024: 3021: 3020: 3005: 3001: 2979: 2978: 2976: 2973: 2972: 2971: 2966: 2961: 2956: 2951: 2946: 2939: 2936: 2935: 2934: 2923: 2903: 2900: 2878: = Â± 2858:diverges for | 2839: 2820: 2813: 2803: 2802: 2791: 2785: 2782: 2777: 2773: 2768: 2763: 2760: 2757: 2754: 2751: 2728: 2725: 2685: 2679: 2664: 2661: 2616: 2604: 2586: 2585: 2561: 2558: 2555: 2550: 2546: 2516: 2512: 2509: 2506: 2503: 2478: 2474: 2471: 2457: 2446: 2431: 2422: 2419: 2418: 2417: 2406: 2403: 2398: 2395: 2391: 2387: 2383: 2378: 2374: 2370: 2366: 2363: 2360: 2352: 2348: 2344: 2339: 2334: 2330: 2322: 2316: 2313: 2310: 2306: 2280: 2275: 2272: 2267: 2262: 2259: 2239: 2219: 2216: 2213: 2193: 2190: 2187: 2182: 2178: 2174: 2171: 2151: 2131: 2107: 2103: 2100: 2097: 2094: 2072: 2067: 2062: 2059: 2034: 2033: 2022: 2019: 2014: 2011: 2008: 2004: 2000: 1996: 1992: 1989: 1986: 1978: 1974: 1970: 1965: 1960: 1956: 1948: 1927: 1907: 1904: 1901: 1881: 1861: 1858: 1855: 1832: 1822: 1810: 1789: 1785: 1782: 1762: 1751: 1739: 1719: 1704: 1701: 1700: 1699: 1685: 1680: 1658: 1653: 1648: 1643: 1638: 1633: 1627: 1621: 1618: 1598: 1583: 1569: 1564: 1540: 1535: 1520: → 1510: 1504: 1497:absolute value 1489: 1488: 1487: 1486: 1481: 1476: 1464: 1463: 1462: 1447: 1439: 1425: 1401:The following 1394: 1391: 1367: 1347: 1327: 1307: 1287: 1262: 1255: 1232: 1229: 1226: 1221: 1214: 1191: 1166: 1162: 1141: 1121: 1118: 1115: 1112: 1101: 1100: 1087: 1083: 1077: 1073: 1069: 1066: 1063: 1057: 1054: 1049: 1044: 1040: 1036: 1031: 1028: 1025: 1021: 1012: 1007: 1004: 1001: 997: 993: 990: 987: 984: 981: 969:in its domain 956: 952: 938:such that the 918: 914: 893: 873: 870: 867: 864: 836: 833: 828: 824: 820: 815: 811: 799: 798: 787: 784: 779: 775: 769: 765: 761: 758: 755: 750: 746: 742: 739: 734: 730: 726: 723: 720: 715: 711: 707: 702: 698: 694: 689: 684: 678: 674: 670: 667: 663: 656: 652: 646: 641: 638: 635: 631: 627: 624: 621: 618: 615: 592: 589: 584: 580: 555: 528: 516: 513: 490: 486: 455: 451: 424: 420: 393: 389: 337: 336: 334: 333: 326: 319: 311: 308: 307: 306: 305: 290: 289: 288: 287: 282: 277: 272: 267: 262: 260:Leonhard Euler 257: 249: 248: 242: 241: 235: 234: 233: 232: 227: 222: 217: 212: 207: 202: 197: 195:Laurent series 192: 190:Winding number 187: 182: 177: 172: 164: 163: 157: 156: 155: 154: 149: 144: 139: 134: 126: 125: 119: 118: 117: 116: 111: 106: 101: 96: 88: 87: 81: 80: 72: 71: 65: 64: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 3367: 3356: 3353: 3352: 3350: 3341: 3338: 3333: 3332: 3327: 3324: 3319: 3315: 3311: 3310: 3305: 3301: 3300: 3296: 3290: 3288:0-8176-4264-1 3284: 3280: 3276: 3272: 3268: 3264: 3258: 3254: 3250: 3246: 3242: 3241: 3237: 3229: 3224: 3221: 3210: 3206: 3200: 3197: 3192: 3188: 3183: 3178: 3174: 3170: 3166: 3159: 3156: 3153:, p. 15. 3152: 3147: 3144: 3139: 3135: 3131: 3129:0-8493-8273-4 3125: 3121: 3120: 3112: 3109: 3105: 3103: 3099: 3095: 3088: 3084: 3080: 3073: 3069: 3065: 3061: 3055: 3053:0-07-010855-2 3049: 3045: 3040: 3039: 3030: 3027: 3003: 2999: 2990: 2987:This implies 2984: 2981: 2974: 2970: 2967: 2965: 2962: 2960: 2957: 2955: 2952: 2950: 2947: 2945: 2942: 2941: 2937: 2932: 2927: 2924: 2921: 2917: 2913: 2912: 2911: 2909: 2901: 2899: 2897: 2893: 2889: 2885: 2881: 2877: 2873: 2868: 2863: 2861: 2855: 2851: 2847: 2838: 2834: 2830: 2826: 2819: 2812: 2808: 2789: 2783: 2780: 2775: 2771: 2766: 2761: 2755: 2749: 2742: 2741: 2740: 2738: 2735:According to 2733: 2726: 2724: 2722: 2721: 2716: 2712: 2708: 2703: 2701: 2662: 2660: 2658: 2653: 2650: 2648: 2644: 2640: 2636: 2632: 2628: 2624: 2619: 2615: 2611: 2607: 2600: 2596: 2592: 2583: 2579: 2578:supremum norm 2575: 2544: 2535: 2531: 2530:FrĂ©chet space 2504: 2501: 2493: 2472: 2462: 2458: 2455: 2451: 2447: 2444: 2440: 2436: 2432: 2429: 2425: 2424: 2420: 2404: 2401: 2396: 2393: 2385: 2376: 2372: 2368: 2361: 2350: 2346: 2337: 2332: 2320: 2314: 2311: 2308: 2296: 2295: 2294: 2278: 2273: 2270: 2260: 2257: 2237: 2217: 2214: 2211: 2188: 2176: 2172: 2169: 2149: 2129: 2120: 2098: 2095: 2092: 2070: 2060: 2057: 2048: 2046: 2041: 2039: 2020: 2017: 2012: 2009: 2006: 2002: 1998: 1994: 1987: 1976: 1972: 1968: 1963: 1958: 1954: 1946: 1925: 1905: 1902: 1899: 1879: 1859: 1856: 1853: 1846: 1830: 1823: 1808: 1783: 1780: 1760: 1752: 1737: 1717: 1710: 1709: 1708: 1702: 1683: 1651: 1631: 1619: 1616: 1596: 1588: 1584: 1567: 1538: 1523: 1519: 1515: 1511: 1508: 1505: 1502: 1498: 1494: 1493: 1492: 1485: 1482: 1480: 1477: 1475: 1472: 1471: 1469: 1465: 1460: 1456: 1452: 1448: 1445: 1438: 1434: 1430: 1426: 1423: 1419: 1415: 1411: 1407: 1406: 1404: 1400: 1399: 1398: 1392: 1390: 1388: 1384: 1379: 1365: 1345: 1325: 1305: 1285: 1276: 1260: 1243:, or just by 1227: 1219: 1189: 1181: 1164: 1160: 1139: 1116: 1110: 1103:converges to 1085: 1075: 1071: 1067: 1064: 1055: 1052: 1042: 1038: 1026: 1019: 1005: 1002: 999: 995: 991: 985: 979: 972: 971: 970: 954: 950: 942:at any point 941: 940:Taylor series 937: 932: 916: 912: 891: 868: 862: 854: 850: 834: 831: 826: 822: 818: 813: 809: 785: 782: 777: 767: 763: 759: 756: 748: 744: 740: 732: 728: 724: 721: 713: 709: 705: 700: 696: 692: 687: 682: 676: 672: 668: 665: 661: 654: 650: 639: 636: 633: 629: 625: 619: 613: 606: 605: 604: 590: 587: 582: 578: 569: 553: 546: 542: 541:real analytic 526: 514: 512: 510: 506: 488: 484: 475: 474:Taylor series 471: 470:Taylor series 453: 449: 440: 422: 418: 409: 391: 387: 378: 377:Taylor series 373: 371: 367: 363: 359: 356: 352: 348: 344: 332: 327: 325: 320: 318: 313: 312: 310: 309: 304: 299: 294: 293: 292: 291: 286: 283: 281: 278: 276: 273: 271: 268: 266: 263: 261: 258: 256: 253: 252: 251: 250: 247: 243: 240: 236: 231: 228: 226: 223: 221: 220:Schwarz lemma 218: 216: 215:Conformal map 213: 211: 208: 206: 203: 201: 198: 196: 193: 191: 188: 186: 183: 181: 178: 176: 173: 171: 168: 167: 166: 165: 162: 158: 153: 150: 148: 145: 143: 140: 138: 135: 133: 130: 129: 128: 127: 124: 120: 115: 112: 110: 107: 105: 104:Complex plane 102: 100: 97: 95: 92: 91: 90: 89: 86: 82: 78: 74: 73: 70: 66: 62: 58: 54: 53: 48: 44: 37: 33: 19: 3329: 3307: 3278: 3248: 3223: 3212:. Retrieved 3208: 3199: 3175:(3): 90–93. 3172: 3168: 3158: 3146: 3118: 3111: 3101: 3100:. The term 3097: 3093: 3086: 3082: 3078: 3071: 3067: 3063: 3059: 3057: 3037: 3029: 2983: 2908:power series 2905: 2887: 2883: 2879: 2875: 2871: 2864: 2859: 2853: 2849: 2845: 2836: 2817: 2810: 2804: 2734: 2730: 2718: 2714: 2704: 2666: 2654: 2651: 2642: 2638: 2634: 2630: 2622: 2617: 2613: 2602: 2587: 2582:Banach space 2491: 2453: 2428:compositions 2121: 2049: 2042: 2035: 1706: 1521: 1517: 1490: 1443: 1436: 1432: 1417: 1413: 1396: 1382: 1380: 1277: 1102: 933: 800: 540: 518: 408:neighborhood 374: 365: 361: 358:power series 346: 340: 161:Basic theory 136: 60: 3102:holomorphic 3058:A function 2713:, the term 2641:containing 2629:to a point 2593:inside its 1845:compact set 1410:polynomials 1387:holomorphic 1278:A function 570:if for any 515:Definitions 343:mathematics 275:Kiyoshi Oka 94:Real number 3238:References 3214:2020-08-30 2536:. The set 2490:, the set 2439:derivative 2435:reciprocal 1457:, and the 853:convergent 410:for every 355:convergent 3331:MathWorld 3314:EMS Press 3191:0021-4280 3070:at point 2684:∞ 2627:converges 2557:Ω 2549:∞ 2511:→ 2508:Ω 2473:⊆ 2470:Ω 2402:α 2386:α 2373:≤ 2351:α 2343:∂ 2333:α 2329:∂ 2312:∈ 2271:≥ 2261:∈ 2258:α 2215:⊆ 2181:∞ 2173:∈ 2102:→ 2061:⊂ 1999:≤ 1903:∈ 1857:⊂ 1784:⊂ 1637:∞ 1620:∈ 1516:function 1455:logarithm 1358:on which 1261:ω 1220:ω 1180:pointwise 1068:− 1011:∞ 996:∑ 835:… 786:⋯ 760:− 725:− 669:− 645:∞ 630:∑ 588:∈ 568:real line 3349:Category 3277:(2002). 3247:(1978). 3138:28890674 3068:analytic 2938:See also 2916:discrete 2867:open set 2829:interval 2610:sequence 2461:open set 2459:For any 1393:Examples 545:open set 351:function 3316:, 2001 2608:) is a 2574:bounded 2572:of all 566:in the 507:or the 437:in its 3285:  3259:  3189:  3136:  3126:  3050:  2595:domain 2450:smooth 1585:Other 849:series 543:on an 439:domain 379:about 246:People 2975:Notes 2580:is a 2528:is a 2122:Then 1466:Most 349:is a 345:, an 3283:ISBN 3257:ISBN 3187:ISSN 3134:OCLC 3124:ISBN 3048:ISBN 2896:pole 2844:1 − 2833:disk 2807:ball 2454:once 2433:The 1512:The 1495:The 1449:The 1427:The 1408:All 1132:for 884:for 364:and 3177:doi 3066:is 2856:... 2305:sup 2119:. 2047:. 1553:to 1338:of 855:to 851:is 539:is 341:In 34:or 3351:: 3328:. 3312:, 3306:, 3273:; 3251:. 3207:. 3185:. 3173:36 3171:. 3167:. 3132:. 3056:. 3046:. 3044:46 2870:ƒ( 2852:− 2848:+ 2723:. 2649:. 2445:.) 1453:, 1405:: 931:. 511:. 59:→ 3334:. 3291:. 3265:. 3230:. 3217:. 3193:. 3179:: 3140:. 3098:R 3094:R 3090:0 3087:z 3083:z 3079:z 3075:0 3072:z 3064:z 3060:f 3018:. 3004:0 3000:x 2933:. 2922:. 2888:x 2884:x 2880:i 2876:x 2872:x 2860:x 2854:x 2850:x 2846:x 2840:0 2837:x 2821:0 2818:x 2814:0 2811:x 2790:. 2784:1 2781:+ 2776:2 2772:x 2767:1 2762:= 2759:) 2756:x 2753:( 2750:f 2678:C 2643:r 2639:D 2635:D 2631:r 2623:n 2618:n 2614:r 2605:n 2603:r 2584:. 2560:) 2554:( 2545:A 2515:C 2505:: 2502:u 2492:A 2477:C 2405:! 2397:1 2394:+ 2390:| 2382:| 2377:C 2369:| 2365:) 2362:x 2359:( 2347:x 2338:f 2321:| 2315:K 2309:x 2279:n 2274:0 2266:Z 2238:C 2218:U 2212:K 2192:) 2189:U 2186:( 2177:C 2170:f 2150:U 2130:f 2106:R 2099:U 2096:: 2093:f 2071:n 2066:R 2058:U 2021:! 2018:k 2013:1 2010:+ 2007:k 2003:C 1995:| 1991:) 1988:x 1985:( 1977:k 1973:x 1969:d 1964:f 1959:k 1955:d 1947:| 1926:k 1906:K 1900:x 1880:C 1860:D 1854:K 1831:f 1821:. 1809:D 1788:C 1781:G 1761:f 1750:. 1738:D 1718:f 1698:. 1684:n 1679:R 1657:) 1652:n 1647:R 1642:( 1632:0 1626:C 1617:f 1597:f 1582:. 1568:2 1563:R 1539:2 1534:R 1522:z 1518:z 1444:x 1440:0 1437:x 1433:x 1424:. 1418:n 1414:n 1366:f 1346:x 1326:D 1306:x 1286:f 1254:C 1231:) 1228:D 1225:( 1213:C 1190:D 1165:0 1161:x 1140:x 1120:) 1117:x 1114:( 1111:f 1086:n 1082:) 1076:0 1072:x 1065:x 1062:( 1056:! 1053:n 1048:) 1043:0 1039:x 1035:( 1030:) 1027:n 1024:( 1020:f 1006:0 1003:= 1000:n 992:= 989:) 986:x 983:( 980:T 955:0 951:x 917:0 913:x 892:x 872:) 869:x 866:( 863:f 832:, 827:1 823:a 819:, 814:0 810:a 783:+ 778:2 774:) 768:0 764:x 757:x 754:( 749:2 745:a 741:+ 738:) 733:0 729:x 722:x 719:( 714:1 710:a 706:+ 701:0 697:a 693:= 688:n 683:) 677:0 673:x 666:x 662:( 655:n 651:a 640:0 637:= 634:n 626:= 623:) 620:x 617:( 614:f 591:D 583:0 579:x 554:D 527:f 489:0 485:x 454:0 450:x 423:0 419:x 392:0 388:x 330:e 323:t 316:v 49:. 38:. 20:)

Index

Real analytic function
analytic expression
analytic signal
holomorphic function
Window function (SQL)
Mathematical analysis
Complex analysis

Complex numbers
Real number
Imaginary number
Complex plane
Complex conjugate
Unit complex number
Complex functions
Complex-valued function
Analytic function
Holomorphic function
Cauchy–Riemann equations
Formal power series
Basic theory
Zeros and poles
Cauchy's integral theorem
Local primitive
Cauchy's integral formula
Winding number
Laurent series
Isolated singularity
Residue theorem
Argument principle

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