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Inverse element

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5504: 4941: 5499:{\displaystyle {\begin{aligned}AA^{\text{T}}&={\begin{bmatrix}1&2&3\\4&5&6\end{bmatrix}}{\begin{bmatrix}1&4\\2&5\\3&6\end{bmatrix}}={\begin{bmatrix}14&32\\32&77\end{bmatrix}}\\\left(AA^{\text{T}}\right)^{-1}&={\begin{bmatrix}14&32\\32&77\end{bmatrix}}^{-1}={\frac {1}{54}}{\begin{bmatrix}77&-32\\-32&14\end{bmatrix}}\\A^{\text{T}}\left(AA^{\text{T}}\right)^{-1}&={\frac {1}{54}}{\begin{bmatrix}1&4\\2&5\\3&6\end{bmatrix}}{\begin{bmatrix}77&-32\\-32&14\end{bmatrix}}={\frac {1}{18}}{\begin{bmatrix}-17&8\\-2&2\\13&-4\end{bmatrix}}=A_{\text{right}}^{-1}\end{aligned}}} 5703: 3914:
have an inverse as defined in this section. Under this more general definition, inverses need not be unique (or exist) in an arbitrary semigroup or monoid. If all elements are regular, then the semigroup (or monoid) is called regular, and every element has at least one inverse. If every element has
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A matrix has a left inverse if and only if its rank equals its number of columns. This left inverse is not unique except for square matrices where the left inverse equal the inverse matrix. Similarly, a right inverse exists if and only if the rank equals the number of rows; it is not unique in the
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The definition in the previous section generalizes the notion of inverse in group relative to the notion of identity. It's also possible, albeit less obvious, to generalize the notion of an inverse by dropping the identity element but keeping associativity; that is, in a
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is a field, the determinant is invertible if and only if it is not zero. As the case of fields is more common, one see often invertible matrices defined as matrices with a nonzero determinant, but this is incorrect over rings.
5698:{\displaystyle A^{\text{T}}A={\begin{bmatrix}1&4\\2&5\\3&6\end{bmatrix}}{\begin{bmatrix}1&2&3\\4&5&6\end{bmatrix}}={\begin{bmatrix}17&22&27\\22&29&36\\27&36&45\end{bmatrix}}} 4933: 1865:
Given a monoid, one may want extend it by adding inverse to some elements. This is generally impossible for non-commutative monoids, but, in a commutative monoid, it is possible to add inverses to the elements that have the
3930:. This is generally justified because in most applications (for example, all examples in this article) associativity holds, which makes this notion a generalization of the left/right inverse relative to an identity (see 4946: 1073: 4745: 2793:. An invertible homomorphism or morphism is called an isomorphism. An homomorphism of algebraic structures is an isomorphism if and only if it is a bijection. The inverse of a bijection is called an 2768: 642: 4526: 4373: 2568: 1287: 2659: 4531: 4378: 500: 319: 290: 4753:
matrix has any (even one-sided) inverse. However, the Moore–Penrose inverse exists for all matrices, and coincides with the left or right (or true) inverse when it exists.
2528: 1146: 1614: 2186: 1470: 1401: 2224:(that is, a ring whose multiplication is not commutative), a non-invertible element may have one or several left or right inverses. This is, for example, the case of the 1501: 1108: 969: 3894:
In a monoid, the notion of inverse as defined in the previous section is strictly narrower than the definition given in this section. Only elements in the Green class
2625: 2951: 2594: 1437: 760: 2156: 1367: 3980:, this is not necessarily the case. In order to obtain interesting notion(s), the unary operation must somehow interact with the semigroup operation. Two classes of 2919: 1712: 875: 3446: 3348: 3246: 2983: 1965: 1904: 4665: 3668: 1933: 1029: 719: 3891:. An intuitive description of this fact is that every pair of mutually inverse elements produces a local left identity, and respectively, a local right identity. 1992: 1568: 1542: 1330: 797: 690: 1778: 1755: 1000: 424: 4318: 4294: 4264: 4236: 4213: 3639: 3603: 3203: 3179: 3159: 3131: 3111: 3091: 3071: 3047: 3027: 3003: 2890: 2859: 2715: 2683: 1732: 560: 4762: 1786:
represents the finite sequences of elementary moves. The inverse of such a sequence is obtained by applying the inverse of each move in the reverse order.
2433:(that is, matrices with integer entries), an invertible matrix is a matrix that has an inverse that is also an integer matrix. Such a matrix is called a 908:
Left and right inverses do not always exist, even when the operation is total and associative. For example, addition is a total associative operation on
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is zero, it is impossible for it to have a one-sided inverse; therefore a left inverse or right inverse implies the existence of the other one. See
3613:(an associative unital magma) every element has at most one inverse (as defined in this section). In a monoid, the set of invertible elements is a 1839:, there may exist non-invertible elements that have a left inverse or a right inverse (not both, as, otherwise, the element would be invertible). 935:
An element can have several left inverses and several right inverses, even when the operation is total and associative. For example, consider the
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for which one of the members of the equality is defined; the equality means that the other member of the equality must also be defined.
4121:. Since *-regular semigroups generalize inverse semigroups, the unique element defined this way in a *-regular semigroup is called the 2248: 2025: 975:, which are the functions that divide by two the even numbers, and give any value to odd numbers. Similarly, every function that maps 4678: 1034: 5845: 5825: 2229: 1403:
When there may be a confusion between several operations, the symbol of the operation may be added before the exponent, such as in
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In the common case where the operation is associative, the left and right inverse of an element are equal and unique. Indeed, if
211:, is an element that is invertible under multiplication (this is not ambiguous, as every element is invertible under addition). 5799: 2094:. Because of commutativity, the concepts of left and right inverses are meaningless since they do not differ from inverses. 2734: 4042: 1681: 1179: 593: 4066: 31: 5900: 4074: 2239:(that is, a ring whose multiplication is commutative) may be extended by adding inverses to elements that are not 5895: 4070: 4009: 1175: 263:, where the (multiplicative) inverse is obtained by exchanging the numerator and the denominator (the inverse of 4026: 2779: 1670: 175:
has both a left inverse and a right inverse, then these two inverses are equal and unique; they are called the
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A natural generalization of the inverse semigroup is to define an (arbitrary) unary operation ° such that (
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over a ring: a homomorphism of modules that has a left inverse of a right inverse is called respectively a
2481: 2118: 1843: 1662: 1504: 1215: 936: 377: 260: 188: 57: 4628:{\displaystyle A\underbrace {A^{\text{T}}\left(AA^{\text{T}}\right)^{-1}} _{A_{\text{right}}^{-1}}=I_{m}} 3248:
may have multiple left, right or two-sided inverses. For example, in the magma given by the Cayley table
5768: 4475:{\displaystyle \underbrace {\left(A^{\text{T}}A\right)^{-1}A^{\text{T}}} _{A_{\text{left}}^{-1}}A=I_{n}} 4239: 2307: 2275: 1867: 1799: 1655: 803: 527: 365: 3455:
Similarly, a loop need not have two-sided inverses. For example, in the loop given by the Cayley table
1783: 3919:. Finally, an inverse semigroup with only one idempotent is a group. An inverse semigroup may have an 2533: 5760: 4138: 3895: 3870: 3609:
then if an element has both a left inverse and a right inverse, they are equal. In other words, in a
2817: 2718: 2686: 2461: 2279: 1847: 1473: 1156: 972: 831: 531: 443: 369: 357: 295: 266: 226:. They are also commonly used for operations that are not defined for all possible operands, such as 2501: 4672: 4216: 3931: 3733: 3614: 2473: 2283: 2221: 2210: 2045: 1859: 1814: 1647: 1573: 1113: 909: 215: 5800:"MIT Professor Gilbert Strang Linear Algebra Lecture #33 – Left and Right Inverses; Pseudoinverse" 4184:
and one uniquely determines the other. They are not left or right inverses of each other however.
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with a type ⟨2,1⟩ algebra. A semigroup endowed with such an operation is called a
1479: 1086: 5841: 5821: 5764: 5756: 4267: 4157: 3920: 3916: 3686: 2924: 2866: 2821: 2783: 2775: 2573: 2465: 2434: 2391: 2072: 1651: 1406: 917: 827: 724: 563: 396: 361: 353: 2263:. Localization is also used with zero divisors, but, in this case the original ring is not a 2128: 1339: 5890: 4274: 4073:(in the sense of Drazin), yield one of best known examples of a (unique) pseudoinverse, the 3926:
Outside semigroup theory, a unique inverse as defined in this section is sometimes called a
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case of a rectangular matrix, and equals the inverse matrix in the case of a square matrix.
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is a monoid for ring multiplication. In this case, the invertible elements are also called
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that are everywhere defined (that is, the operation is defined for any two elements of its
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that means 'turned upside down', 'overturned'. This may take its origin from the case of
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is an invertible element under matrix multiplication. A matrix over a commutative ring
2005: 1829: 1717: 1076: 929: 834:, and the composition of the identity functions of two different sets are not defined. 545: 250: 4833:{\displaystyle A:2\times 3={\begin{bmatrix}1&2&3\\4&5&6\end{bmatrix}}} 4041:-semigroup and a *-semigroup. A class of semigroups important in semigroup theory are 5884: 5721: 4668: 4193: 3829:. Thus, every pair of (mutually) inverse elements gives rise to two idempotents, and 2376: 2372: 2291: 2240: 2214: 2060: 388:
must be extended to partial operations; this is the object of the first subsections.
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The usual definition of an identity element has been generalized for including the
3449: 3351: 2813: 2469: 1677: 1619: 400: 4928:{\displaystyle A_{\text{right}}^{-1}=A^{\text{T}}\left(AA^{\text{T}}\right)^{-1}.} 403:) on which a partial operation (possibly total) is defined, which is denoted with 4243: 3915:
exactly one inverse as defined in this section, then the semigroup is called an
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of the localisation; instead, it is mapped non-injectively to the localization.
2068: 2064: 1635: 1623: 1370: 434: 325: 239: 168: 38: 2101:; this means that multiplication is associative and has an identity called the 5726: 3903:
have an inverse from the unital magma perspective, whereas for any idempotent
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defines a transformation that is the inverse of the transformation defined by
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Monoids, Acts and Categories with Applications to Wreath Products and Graphs
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that has an identity element, and for which every element has an inverse.
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It follows that a total operation has at most one identity element, and if
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contains all of the semigroup material herein except *-regular semigroups.
5820:, De Gruyter Expositions in Mathematics vol. 29, Walter de Gruyter, 2000, 2441:. A square integer matrix is unimodular if and only if its determinant is 364:, that is operations that are not defined everywhere. Common examples are 4238:
is invertible (in the set of all square matrices of the same size, under
2694: 2662: 2477: 2295: 1631: 373: 243: 4065:°. There are few concrete examples of such semigroups however; most are 2000:
construction. This is the method that is commonly used for constructing
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that is, the transformation that "undoes" the transformation defined by
1673:, since the inverse of the inverse of an element is the element itself. 1665:
from the group to itself that may also be considered as an operation of
2264: 2013: 2001: 183:. Often an adjective is added for specifying the operation, such as in 2449:, since these two numbers are the only units in the ring of integers. 4638:
The left inverse can be used to determine the least norm solution of
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the only element with a two-sided inverse is the identity element 1.
2098: 1795: 5828:, p. 15 (def in unital magma) and p. 33 (def in semigroup) 2804:
A function has a left inverse or a right inverse if and only it is
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every element has a unique two-sided inverse (namely itself), but
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A unital magma in which all elements are invertible need not be a
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acts a right identity, and the left/right roles are reversed for
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for distinguishing it from matrices that are invertible over the
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under an operation if it has a left inverse and a right inverse.
928:. This lack of inverses is the main motivation for extending the 1068:{\textstyle n\mapsto \left\lfloor {\frac {n}{2}}\right\rfloor ,} 4740:{\displaystyle x=\left(A^{\text{T}}A\right)^{-1}A^{\text{T}}b.} 2828:. This terminology is also used for morphisms in any category. 2371:, that is, an identity element for matrix multiplication is a 1295:
of an invertible element is its unique left or right inverse.
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for which the left-hand sides of the equalities are defined.
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All examples in this section involve associative operators.
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In the function and homomorphism cases, this means that the
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If the operation is denoted as an addition, the inverse, or
4061:; in other words every element has commuting pseudoinverse 3785:
as defined in this section. Another easy to prove fact: if
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Nordahl, T.E., and H.E. Scheiblich, Regular * Semigroups,
2121:(for avoiding confusion with additive inverses) of a unit 5859:, Proc. Symp. on Regular Semigroups (DeKalb, 1979), 29–46 4081:* is not the pseudoinverse. Rather, the pseudoinverse of 3205:. An element with an inverse element only on one side is 2243:(that is, their product with a nonzero element cannot be 2056:, which are denoted as the usual operations on numbers. 2488:, and share many properties with function composition. 2375:(same number for rows and columns) whose entries of the 3311:
the elements 2 and 3 each have two two-sided inverses.
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are respectively a left inverse and a right inverse of
360:). However, these concepts are also commonly used with 5637: 5588: 5540: 5419: 5364: 5316: 5210: 5152: 5071: 5020: 4974: 4789: 2164: 1482: 1379: 1116: 1089: 1037: 300: 271: 27:
Generalization of additive and multiplicative inverses
5518: 4944: 4857: 4765: 4681: 4644: 4534: 4490: 4381: 4337: 4306: 4282: 4252: 4224: 4201: 3765:. Every regular element has at least one inverse: if 3647: 3627: 3591: 3422: 3324: 3222: 3191: 3167: 3147: 3119: 3099: 3079: 3059: 3035: 3015: 2991: 2959: 2927: 2901: 2878: 2847: 2737: 2703: 2671: 2633: 2602: 2576: 2536: 2504: 2131: 1974: 1941: 1912: 1880: 1763: 1740: 1720: 1690: 1576: 1550: 1524: 1445: 1409: 1342: 1312: 1218: 1008: 985: 948: 848: 779: 727: 698: 672: 596: 548: 446: 409: 298: 269: 2763:{\displaystyle \operatorname {id} _{X}\colon X\to X} 2255:
from the ring of integers, and, more generally, the
3869:. This simple observation can be generalized using 5697: 5498: 4927: 4832: 4739: 4659: 4627: 4520: 4474: 4367: 4312: 4288: 4258: 4230: 4207: 3662: 3633: 3597: 3440: 3342: 3240: 3197: 3173: 3153: 3125: 3105: 3085: 3065: 3041: 3021: 2997: 2977: 2945: 2913: 2884: 2853: 2762: 2709: 2677: 2653: 2619: 2588: 2562: 2522: 2398:is invertible if and only if its determinant is a 2286:, and straightforwardly extended to matrices over 2180: 2150: 1986: 1959: 1927: 1898: 1850:. In this monoid, the invertible elements are the 1772: 1749: 1726: 1706: 1608: 1562: 1536: 1495: 1464: 1431: 1395: 1361: 1324: 1281: 1163:, and it has a right inverse if and only if it is 1155:More generally, a function has a left inverse for 1140: 1102: 1067: 1023: 994: 963: 869: 791: 754: 721:(This results immediately from the definition, by 713: 684: 637:{\displaystyle x*e=x\quad {\text{and}}\quad e*y=y} 636: 554: 494: 418: 313: 284: 3877:in an arbitrary semigroup is a left identity for 526:Examples of non-total associative operations are 30:"Invertible" redirects here. For other uses, see 3448:is not a loop because the Cayley table is not a 2789:A function is invertible if and only if it is a 4069:. In contrast, a subclass of *-semigroups, the 1854:; the elements that have left inverses are the 124:. (An identity element is an element such that 4246:is different from zero. If the determinant of 3093:is both a left inverse and a right inverse of 2251:, which produces, in particular, the field of 332:, except when otherwise stated and in section 4156:The lower and upper adjoints in a (monotone) 2194:is never a unit, except when the ring is the 1858:, and those that have right inverses are the 8: 4756:As an example of matrix inverses, consider: 3923:0 because 000 = 0, whereas a group may not. 2693:. In the morphism case, this means that the 2627:or, in the function and homomorphism cases, 2158:or, when the multiplication is commutative, 380:. It follows that the common definitions of 195:. In this case (associative operation), an 160:for which the left-hand sides are defined.) 4168:are quasi-inverses of each other; that is, 2213:if the multiplication is commutative, or a 222:—where invertible elements are also called 4049:-semigroups in which one additionally has 5632: 5583: 5535: 5523: 5517: 5483: 5478: 5414: 5404: 5359: 5311: 5301: 5285: 5274: 5255: 5205: 5195: 5183: 5147: 5130: 5119: 5066: 5015: 4969: 4956: 4945: 4943: 4913: 4902: 4883: 4867: 4862: 4856: 4784: 4764: 4725: 4712: 4698: 4680: 4643: 4619: 4601: 4596: 4591: 4576: 4565: 4546: 4539: 4533: 4489: 4466: 4445: 4440: 4435: 4423: 4410: 4396: 4383: 4380: 4336: 4305: 4281: 4251: 4223: 4200: 3646: 3626: 3590: 3421: 3323: 3221: 3190: 3166: 3161:. An element with a two-sided inverse in 3146: 3118: 3098: 3078: 3058: 3034: 3014: 2990: 2958: 2926: 2900: 2877: 2846: 2742: 2736: 2702: 2670: 2632: 2601: 2575: 2535: 2503: 2165: 2163: 2136: 2130: 1996:This extension of a monoid is allowed by 1973: 1940: 1911: 1879: 1762: 1739: 1719: 1695: 1689: 1594: 1581: 1575: 1549: 1523: 1483: 1481: 1450: 1444: 1414: 1408: 1380: 1378: 1347: 1341: 1311: 1217: 1117: 1115: 1090: 1088: 1048: 1036: 1007: 984: 947: 847: 778: 726: 697: 671: 613: 595: 547: 445: 408: 299: 297: 270: 268: 5870:, 24(1), December 1982, pp. 173–187 5509:The left inverse doesn't exist, because 3457: 3355: 3250: 971:has infinitely many left inverses under 218:—where every element is invertible, and 199:is an element that has an inverse. In a 5748: 4273:More generally, a square matrix over a 2306:, because of the use of the concept of 1846:from a set to itself is a monoid under 1684:of this set. In this case, the inverse 939:from the integers to the integers. The 4521:{\displaystyle A:m\times n\mid m<n} 4368:{\displaystyle A:m\times n\mid m>n} 4077:. In this case however the involution 2457:Functions, homomorphisms and morphisms 2300:in this section, only matrices over a 881:is an identity element, one says that 4528:we have right inverses; for example, 4013:, in which the interaction axiom is ( 2484:into operations that are also called 7: 4375:we have left inverses; for example, 3994:, in which the interaction axiom is 2209:is the only non-unit, the ring is a 1282:{\displaystyle l=l*(x*r)=(l*x)*r=r.} 666:are two identity elements such that 333: 324:In this article, the operations are 5816:M. Kilp, U. Knauer, A.V. Mikhalev, 2797:. In the other cases, one talks of 1031:is a right inverse of the function 249:The word 'inverse' is derived from 5857:Regular semigroups with involution 4025:°. Such an operation is called an 2097:Under multiplication, a ring is a 1570:is invertible, and its inverse is 25: 4327:have several one-sided inverses: 4300:its determinant is invertible in 4188:Generalized inverses of matrices 2230:infinite-dimensional vector space 2071:; it has an identity, called the 1874:has the cancellation property if 1174:, right inverses are also called 5834:Fundamentals of Semigroup Theory 4935:By components it is computed as 2563:{\displaystyle g\colon Y'\to Z,} 2491:In all the case, composition is 924:is the only element that has an 340:Definitions and basic properties 5864:P-systems in regular semigroups 3984:-semigroups have been studied: 3773:then it is easy to verify that 2331:matrix (that is, a matrix with 2113:for multiplication is called a 2063:, which means that addition is 1178:, and left inverses are called 773:are different identities, then 618: 612: 566:associative operation on a set 495:{\displaystyle x*(y*z)=(x*y)*z} 314:{\displaystyle {\tfrac {y}{x}}} 285:{\displaystyle {\tfrac {x}{y}}} 234:. This has been generalized to 3657: 3651: 3435: 3423: 3337: 3325: 3235: 3223: 2754: 2551: 2523:{\displaystyle f\colon X\to Y} 2514: 1261: 1249: 1243: 1231: 1141:{\textstyle {\frac {n-1}{2}},} 1041: 952: 483: 471: 465: 453: 214:Inverses are commonly used in 1: 4043:completely regular semigroups 3711:if there exists some element 2685:equals or is included in the 2059:Under addition, a ring is an 1609:{\displaystyle y^{-1}x^{-1}.} 4067:completely simple semigroups 3972:. Although it may seem that 3318:. For example, in the magma 2654:{\displaystyle Y\subset Y'.} 2383:, and all other entries are 2367:, and only in this case. An 2181:{\textstyle {\frac {1}{x}}.} 1842:For example, the set of the 1465:{\displaystyle f^{\circ -1}} 1396:{\textstyle {\frac {1}{x}}.} 802:For example, in the case of 45:generalises the concepts of 4851:, we have a right inverse, 4037:Clearly a group is both an 4029:, and typically denoted by 3857:acts as a left identity on 3216:Elements of a unital magma 2782:), which is called also an 2406:(that is, is invertible in 2083:has an inverse, called its 1496:{\textstyle {\frac {1}{f}}} 1103:{\textstyle {\frac {n}{2}}} 964:{\displaystyle x\mapsto 2x} 819:for every positive integer 238:, where, by definition, an 32:Invertible (disambiguation) 5917: 5712:, and cannot be inverted. 4136: 3684: 2596:is defined if and only if 2247:). This is the process of 1332:Otherwise, the inverse of 830:are identity elements for 528:multiplication of matrices 323: 29: 5780:Howie, prop. 2.3.3, p. 51 5767:as identity elements for 5759:as identity elements for 3976:° will be the inverse of 2778:, algebraic structure or 2016:and, more generally, the 1472:is not commonly used for 352:are commonly defined for 3475: 3472: 3469: 3466: 3463: 3460: 3367: 3364: 3361: 3358: 3262: 3259: 3256: 3253: 2946:{\displaystyle a,b\in S} 2589:{\displaystyle g\circ f} 2278:is commonly defined for 1817:under monoid operation. 1432:{\displaystyle x^{*-1}.} 755:{\displaystyle e=e*f=f.} 5832:Howie, John M. (1995). 4323:Non-square matrices of 3884:and right identity for 2202:as its unique element. 2151:{\displaystyle x^{-1},} 2103:multiplicative identity 1661:Thus, the inverse is a 1362:{\displaystyle x^{-1},} 838:Left and right inverses 530:of arbitrary size, and 433:A partial operation is 5699: 5500: 4929: 4834: 4741: 4661: 4629: 4522: 4476: 4369: 4314: 4290: 4260: 4232: 4209: 4085:is the unique element 3741:is called (simply) an 3731:is sometimes called a 3664: 3635: 3599: 3442: 3344: 3242: 3199: 3175: 3155: 3127: 3107: 3087: 3067: 3043: 3023: 2999: 2979: 2947: 2915: 2914:{\displaystyle e\in S} 2886: 2855: 2786:in the function case. 2764: 2711: 2679: 2655: 2621: 2590: 2564: 2524: 2190:The additive identity 2182: 2152: 2119:multiplicative inverse 1988: 1961: 1929: 1900: 1774: 1751: 1728: 1708: 1707:{\displaystyle g^{-1}} 1610: 1564: 1538: 1505:multiplicative inverse 1497: 1466: 1433: 1397: 1363: 1326: 1283: 1142: 1104: 1069: 1025: 996: 965: 871: 870:{\displaystyle x*y=e,} 793: 756: 715: 686: 638: 556: 496: 420: 334:§ Generalizations 315: 286: 254: 189:multiplicative inverse 5769:matrix multiplication 5727:Latin square property 5700: 5501: 4930: 4835: 4742: 4662: 4630: 4523: 4477: 4370: 4315: 4291: 4261: 4242:) if and only if its 4240:matrix multiplication 4233: 4210: 4127:Moore–Penrose inverse 4075:Moore–Penrose inverse 3709:(von Neumann) regular 3665: 3636: 3600: 3443: 3441:{\displaystyle (S,*)} 3345: 3343:{\displaystyle (S,*)} 3243: 3241:{\displaystyle (S,*)} 3200: 3176: 3156: 3128: 3108: 3088: 3068: 3044: 3024: 3000: 2980: 2978:{\displaystyle a*b=e} 2948: 2916: 2887: 2856: 2765: 2712: 2680: 2656: 2622: 2591: 2565: 2525: 2414:can be computed with 2276:Matrix multiplication 2183: 2153: 2048:with two operations, 1989: 1962: 1960:{\displaystyle yx=zx} 1930: 1901: 1899:{\displaystyle xy=xz} 1868:cancellation property 1800:associative operation 1775: 1752: 1729: 1709: 1656:associative operation 1611: 1565: 1539: 1498: 1467: 1434: 1398: 1369:or, in the case of a 1364: 1336:is generally denoted 1327: 1284: 1159:if and only if it is 1143: 1105: 1070: 1026: 997: 966: 872: 804:matrix multiplication 794: 757: 716: 687: 639: 557: 497: 421: 366:matrix multiplication 316: 287: 18:Inverse (ring theory) 5877:, 16(1978), 369–377. 5761:function composition 5516: 4942: 4855: 4763: 4679: 4667:, which is also the 4660:{\displaystyle Ax=b} 4642: 4532: 4488: 4379: 4335: 4304: 4280: 4250: 4222: 4199: 4139:Quasiregular element 4071:*-regular semigroups 3663:{\displaystyle U(S)} 3645: 3625: 3589: 3420: 3322: 3220: 3189: 3165: 3145: 3117: 3097: 3077: 3057: 3033: 3013: 2989: 2957: 2925: 2899: 2876: 2845: 2799:inverse isomorphisms 2735: 2701: 2669: 2631: 2620:{\displaystyle Y'=Y} 2600: 2574: 2534: 2502: 2474:algebraic structures 2468:that generalizes to 2410:. In this case, its 2353:matrix, the product 2162: 2129: 2079:; and every element 1972: 1939: 1928:{\displaystyle y=z,} 1910: 1878: 1860:surjective functions 1848:function composition 1761: 1738: 1718: 1688: 1574: 1548: 1522: 1518:are invertible, and 1503:can be used for the 1480: 1474:function composition 1443: 1407: 1377: 1340: 1310: 1216: 1157:function composition 1114: 1087: 1035: 1024:{\displaystyle 2n+1} 1006: 983: 973:function composition 946: 910:nonnegative integers 846: 832:function composition 777: 725: 714:{\displaystyle e=f.} 696: 670: 594: 546: 532:function composition 444: 407: 370:function composition 296: 267: 41:, the concept of an 5491: 4875: 4609: 4453: 4123:generalized inverse 3932:Generalized inverse 3873:: every idempotent 2222:noncommutative ring 2111:invertible element 2046:algebraic structure 1987:{\displaystyle y=z} 1856:injective functions 1852:bijective functions 1835:If a monoid is not 1813:in a monoid form a 1811:invertible elements 1714:of a group element 1669:one. It is also an 1563:{\displaystyle x*y} 1537:{\displaystyle x*y} 1325:{\displaystyle -x.} 932:into the integers. 792:{\displaystyle e*f} 685:{\displaystyle e*f} 372:and composition of 163:When the operation 5757:identity functions 5737:Unit (ring theory) 5695: 5689: 5623: 5577: 5496: 5494: 5474: 5465: 5395: 5353: 5241: 5177: 5096: 5057: 5009: 4925: 4858: 4830: 4824: 4737: 4657: 4625: 4611: 4592: 4589: 4518: 4472: 4455: 4436: 4433: 4365: 4310: 4286: 4256: 4228: 4215:with entries in a 4205: 4152:Galois connections 3907:, the elements of 3660: 3631: 3595: 3438: 3340: 3238: 3195: 3171: 3151: 3123: 3103: 3083: 3063: 3039: 3019: 2995: 2975: 2943: 2911: 2882: 2851: 2826:split monomorphism 2760: 2707: 2675: 2651: 2617: 2586: 2560: 2520: 2257:field of fractions 2178: 2148: 2018:field of fractions 1998:Grothendieck group 1984: 1957: 1925: 1896: 1784:Rubik's cube group 1773:{\displaystyle g.} 1770: 1750:{\displaystyle g,} 1747: 1724: 1704: 1634:is also called an 1606: 1560: 1534: 1493: 1462: 1429: 1393: 1359: 1322: 1279: 1148:depending whether 1138: 1100: 1065: 1021: 995:{\displaystyle 2n} 992: 961: 867: 828:identity functions 789: 752: 711: 682: 634: 552: 492: 419:{\displaystyle *.} 416: 362:partial operations 350:invertible element 311: 309: 282: 280: 205:invertible element 197:invertible element 193:functional inverse 5901:Binary operations 5765:identity matrices 5526: 5481: 5412: 5309: 5277: 5258: 5203: 5122: 4959: 4905: 4886: 4865: 4728: 4701: 4599: 4568: 4549: 4540: 4538: 4443: 4426: 4399: 4384: 4382: 4313:{\displaystyle R} 4289:{\displaystyle R} 4268:invertible matrix 4259:{\displaystyle M} 4231:{\displaystyle K} 4208:{\displaystyle M} 4158:Galois connection 3921:absorbing element 3917:inverse semigroup 3871:Green's relations 3789:is an inverse of 3781:is an inverse of 3687:Regular semigroup 3641:, and denoted by 3634:{\displaystyle S} 3598:{\displaystyle *} 3585:If the operation 3580: 3579: 3414: 3413: 3309: 3308: 3198:{\displaystyle S} 3174:{\displaystyle S} 3154:{\displaystyle y} 3135:two-sided inverse 3126:{\displaystyle x} 3106:{\displaystyle y} 3086:{\displaystyle x} 3066:{\displaystyle a} 3042:{\displaystyle b} 3022:{\displaystyle b} 2998:{\displaystyle a} 2885:{\displaystyle *} 2854:{\displaystyle S} 2837:In a unital magma 2822:split epimorphism 2784:identity function 2770:for every object 2710:{\displaystyle f} 2678:{\displaystyle f} 2466:partial operation 2435:unimodular matrix 2392:invertible matrix 2379:are all equal to 2173: 2117:. The inverse or 2073:additive identity 2030:commutative rings 1798:is a set with an 1782:For example, the 1727:{\displaystyle g} 1544:is defined, then 1491: 1388: 1133: 1098: 1056: 941:doubling function 918:additive identity 799:is not defined. 692:is defined, then 616: 555:{\displaystyle *} 538:Identity elements 391:In this section, 354:binary operations 330:identity elements 308: 279: 242:is an invertible 232:inverse functions 16:(Redirected from 5908: 5896:Abstract algebra 5851: 5804: 5803: 5796: 5790: 5787: 5781: 5778: 5772: 5753: 5704: 5702: 5701: 5696: 5694: 5693: 5628: 5627: 5582: 5581: 5528: 5527: 5524: 5505: 5503: 5502: 5497: 5495: 5490: 5482: 5479: 5470: 5469: 5413: 5405: 5400: 5399: 5358: 5357: 5310: 5302: 5293: 5292: 5284: 5280: 5279: 5278: 5275: 5260: 5259: 5256: 5246: 5245: 5204: 5196: 5191: 5190: 5182: 5181: 5138: 5137: 5129: 5125: 5124: 5123: 5120: 5101: 5100: 5062: 5061: 5014: 5013: 4961: 4960: 4957: 4934: 4932: 4931: 4926: 4921: 4920: 4912: 4908: 4907: 4906: 4903: 4888: 4887: 4884: 4874: 4866: 4863: 4839: 4837: 4836: 4831: 4829: 4828: 4746: 4744: 4743: 4738: 4730: 4729: 4726: 4720: 4719: 4711: 4707: 4703: 4702: 4699: 4675:and is given by 4666: 4664: 4663: 4658: 4634: 4632: 4631: 4626: 4624: 4623: 4610: 4608: 4600: 4597: 4590: 4585: 4584: 4583: 4575: 4571: 4570: 4569: 4566: 4551: 4550: 4547: 4527: 4525: 4524: 4519: 4481: 4479: 4478: 4473: 4471: 4470: 4454: 4452: 4444: 4441: 4434: 4429: 4428: 4427: 4424: 4418: 4417: 4409: 4405: 4401: 4400: 4397: 4374: 4372: 4371: 4366: 4319: 4317: 4316: 4311: 4295: 4293: 4292: 4287: 4275:commutative ring 4265: 4263: 4262: 4257: 4237: 4235: 4234: 4229: 4214: 4212: 4211: 4206: 3669: 3667: 3666: 3661: 3640: 3638: 3637: 3632: 3604: 3602: 3601: 3596: 3458: 3447: 3445: 3444: 3439: 3356: 3349: 3347: 3346: 3341: 3251: 3247: 3245: 3244: 3239: 3211:right invertible 3204: 3202: 3201: 3196: 3180: 3178: 3177: 3172: 3160: 3158: 3157: 3152: 3132: 3130: 3129: 3124: 3112: 3110: 3109: 3104: 3092: 3090: 3089: 3084: 3073:. If an element 3072: 3070: 3069: 3064: 3048: 3046: 3045: 3040: 3028: 3026: 3025: 3020: 3004: 3002: 3001: 2996: 2984: 2982: 2981: 2976: 2952: 2950: 2949: 2944: 2920: 2918: 2917: 2912: 2894:identity element 2891: 2889: 2888: 2883: 2871:binary operation 2860: 2858: 2857: 2852: 2795:inverse function 2773: 2769: 2767: 2766: 2761: 2747: 2746: 2724: 2716: 2714: 2713: 2708: 2692: 2684: 2682: 2681: 2676: 2660: 2658: 2657: 2652: 2647: 2626: 2624: 2623: 2618: 2610: 2595: 2593: 2592: 2587: 2570:the composition 2569: 2567: 2566: 2561: 2550: 2529: 2527: 2526: 2521: 2448: 2444: 2431:integer matrices 2424: 2409: 2405: 2397: 2386: 2382: 2366: 2356: 2352: 2342: 2338: 2334: 2330: 2320: 2302:commutative ring 2253:rational numbers 2246: 2237:commutative ring 2226:linear functions 2208: 2201: 2193: 2187: 2185: 2184: 2179: 2174: 2166: 2157: 2155: 2154: 2149: 2144: 2143: 2124: 2108: 2093: 2085:additive inverse 2082: 2078: 2010:rational numbers 1995: 1993: 1991: 1990: 1985: 1966: 1964: 1963: 1958: 1934: 1932: 1931: 1926: 1905: 1903: 1902: 1897: 1873: 1804:identity element 1779: 1777: 1776: 1771: 1756: 1754: 1753: 1748: 1733: 1731: 1730: 1725: 1713: 1711: 1710: 1705: 1703: 1702: 1630:, an invertible 1615: 1613: 1612: 1607: 1602: 1601: 1589: 1588: 1569: 1567: 1566: 1561: 1543: 1541: 1540: 1535: 1517: 1513: 1502: 1500: 1499: 1494: 1492: 1484: 1471: 1469: 1468: 1463: 1461: 1460: 1438: 1436: 1435: 1430: 1425: 1424: 1402: 1400: 1399: 1394: 1389: 1381: 1368: 1366: 1365: 1360: 1355: 1354: 1335: 1331: 1329: 1328: 1323: 1305: 1302:, of an element 1300:additive inverse 1288: 1286: 1285: 1280: 1208: 1204: 1200: 1152:is even or odd. 1151: 1147: 1145: 1144: 1139: 1134: 1129: 1118: 1109: 1107: 1106: 1101: 1099: 1091: 1082: 1074: 1072: 1071: 1066: 1061: 1057: 1049: 1030: 1028: 1027: 1022: 1001: 999: 998: 993: 978: 970: 968: 967: 962: 926:additive inverse 923: 915: 904: 896: 892: 884: 880: 876: 874: 873: 868: 822: 815: 798: 796: 795: 790: 772: 768: 761: 759: 758: 753: 720: 718: 717: 712: 691: 689: 688: 683: 665: 661: 654: 650: 643: 641: 640: 635: 617: 614: 586: 576:identity element 569: 561: 559: 558: 553: 522: 518: 501: 499: 498: 493: 425: 423: 422: 417: 394: 386:identity element 344:The concepts of 320: 318: 317: 312: 310: 301: 291: 289: 288: 283: 281: 272: 228:inverse matrices 207:, also called a 185:additive inverse 174: 171:, if an element 166: 159: 155: 151: 137: 123: 115: 111: 103: 100:, one says that 99: 85: 80:identity element 77: 66: 55: 21: 5916: 5915: 5911: 5910: 5909: 5907: 5906: 5905: 5881: 5880: 5875:Semigroup Forum 5868:Semigroup Forum 5862:Miyuki Yamada, 5848: 5838:Clarendon Press 5831: 5813: 5808: 5807: 5798: 5797: 5793: 5788: 5784: 5779: 5775: 5754: 5750: 5745: 5718: 5710:singular matrix 5688: 5687: 5682: 5677: 5671: 5670: 5665: 5660: 5654: 5653: 5648: 5643: 5633: 5622: 5621: 5616: 5611: 5605: 5604: 5599: 5594: 5584: 5576: 5575: 5570: 5564: 5563: 5558: 5552: 5551: 5546: 5536: 5519: 5514: 5513: 5493: 5492: 5464: 5463: 5455: 5449: 5448: 5443: 5434: 5433: 5428: 5415: 5394: 5393: 5388: 5379: 5378: 5370: 5360: 5352: 5351: 5346: 5340: 5339: 5334: 5328: 5327: 5322: 5312: 5294: 5270: 5266: 5262: 5261: 5251: 5248: 5247: 5240: 5239: 5234: 5225: 5224: 5216: 5206: 5176: 5175: 5170: 5164: 5163: 5158: 5148: 5146: 5139: 5115: 5111: 5107: 5106: 5103: 5102: 5095: 5094: 5089: 5083: 5082: 5077: 5067: 5056: 5055: 5050: 5044: 5043: 5038: 5032: 5031: 5026: 5016: 5008: 5007: 5002: 4997: 4991: 4990: 4985: 4980: 4970: 4962: 4952: 4940: 4939: 4898: 4894: 4890: 4889: 4879: 4853: 4852: 4823: 4822: 4817: 4812: 4806: 4805: 4800: 4795: 4785: 4761: 4760: 4721: 4694: 4693: 4689: 4688: 4677: 4676: 4640: 4639: 4615: 4561: 4557: 4553: 4552: 4542: 4541: 4530: 4529: 4486: 4485: 4462: 4419: 4392: 4391: 4387: 4386: 4385: 4377: 4376: 4333: 4332: 4302: 4301: 4278: 4277: 4248: 4247: 4220: 4219: 4197: 4196: 4190: 4154: 4146: 4141: 4135: 3943: 3913: 3901: 3889: 3882: 3699:In a semigroup 3689: 3683: 3676: 3643: 3642: 3623: 3622: 3587: 3586: 3418: 3417: 3320: 3319: 3218: 3217: 3207:left invertible 3187: 3186: 3163: 3162: 3143: 3142: 3137:, or simply an 3115: 3114: 3095: 3094: 3075: 3074: 3055: 3054: 3031: 3030: 3011: 3010: 2987: 2986: 2955: 2954: 2923: 2922: 2897: 2896: 2874: 2873: 2843: 2842: 2839: 2834: 2832:Generalizations 2771: 2738: 2733: 2732: 2722: 2699: 2698: 2690: 2667: 2666: 2640: 2629: 2628: 2603: 2598: 2597: 2572: 2571: 2543: 2532: 2531: 2500: 2499: 2459: 2446: 2442: 2429:In the case of 2422: 2407: 2403: 2395: 2384: 2380: 2369:identity matrix 2358: 2354: 2344: 2340: 2336: 2332: 2322: 2318: 2273: 2261:integral domain 2244: 2206: 2199: 2191: 2160: 2159: 2132: 2127: 2126: 2122: 2106: 2088: 2080: 2076: 2038: 2022:integral domain 2006:natural numbers 1970: 1969: 1968: 1937: 1936: 1908: 1907: 1876: 1875: 1871: 1792: 1759: 1758: 1736: 1735: 1716: 1715: 1691: 1686: 1685: 1682:transformations 1644: 1628:category theory 1590: 1577: 1572: 1571: 1546: 1545: 1520: 1519: 1515: 1511: 1478: 1477: 1446: 1441: 1440: 1410: 1405: 1404: 1375: 1374: 1373:multiplication 1343: 1338: 1337: 1333: 1308: 1307: 1303: 1214: 1213: 1206: 1202: 1198: 1188: 1172:category theory 1149: 1119: 1112: 1111: 1085: 1084: 1080: 1044: 1033: 1032: 1004: 1003: 981: 980: 976: 944: 943: 930:natural numbers 921: 913: 902: 894: 890: 882: 878: 844: 843: 840: 820: 817:identity matrix 807: 806:, there is one 775: 774: 770: 766: 723: 722: 694: 693: 668: 667: 663: 659: 652: 648: 592: 591: 584: 579:, or simply an 567: 544: 543: 540: 520: 506: 442: 441: 431: 405: 404: 392: 346:inverse element 342: 337: 294: 293: 265: 264: 236:category theory 177:inverse element 172: 164: 157: 153: 139: 125: 121: 113: 109: 101: 87: 83: 75: 67:) of numbers. 61: 50: 43:inverse element 35: 28: 23: 22: 15: 12: 11: 5: 5914: 5912: 5904: 5903: 5898: 5893: 5883: 5882: 5879: 5878: 5871: 5860: 5855:Drazin, M.P., 5853: 5846: 5829: 5812: 5809: 5806: 5805: 5791: 5782: 5773: 5747: 5746: 5744: 5741: 5740: 5739: 5734: 5732:Loop (algebra) 5729: 5724: 5717: 5714: 5706: 5705: 5692: 5686: 5683: 5681: 5678: 5676: 5673: 5672: 5669: 5666: 5664: 5661: 5659: 5656: 5655: 5652: 5649: 5647: 5644: 5642: 5639: 5638: 5636: 5631: 5626: 5620: 5617: 5615: 5612: 5610: 5607: 5606: 5603: 5600: 5598: 5595: 5593: 5590: 5589: 5587: 5580: 5574: 5571: 5569: 5566: 5565: 5562: 5559: 5557: 5554: 5553: 5550: 5547: 5545: 5542: 5541: 5539: 5534: 5531: 5522: 5507: 5506: 5489: 5486: 5477: 5473: 5468: 5462: 5459: 5456: 5454: 5451: 5450: 5447: 5444: 5442: 5439: 5436: 5435: 5432: 5429: 5427: 5424: 5421: 5420: 5418: 5411: 5408: 5403: 5398: 5392: 5389: 5387: 5384: 5381: 5380: 5377: 5374: 5371: 5369: 5366: 5365: 5363: 5356: 5350: 5347: 5345: 5342: 5341: 5338: 5335: 5333: 5330: 5329: 5326: 5323: 5321: 5318: 5317: 5315: 5308: 5305: 5300: 5297: 5295: 5291: 5288: 5283: 5273: 5269: 5265: 5254: 5250: 5249: 5244: 5238: 5235: 5233: 5230: 5227: 5226: 5223: 5220: 5217: 5215: 5212: 5211: 5209: 5202: 5199: 5194: 5189: 5186: 5180: 5174: 5171: 5169: 5166: 5165: 5162: 5159: 5157: 5154: 5153: 5151: 5145: 5142: 5140: 5136: 5133: 5128: 5118: 5114: 5110: 5105: 5104: 5099: 5093: 5090: 5088: 5085: 5084: 5081: 5078: 5076: 5073: 5072: 5070: 5065: 5060: 5054: 5051: 5049: 5046: 5045: 5042: 5039: 5037: 5034: 5033: 5030: 5027: 5025: 5022: 5021: 5019: 5012: 5006: 5003: 5001: 4998: 4996: 4993: 4992: 4989: 4986: 4984: 4981: 4979: 4976: 4975: 4973: 4968: 4965: 4963: 4955: 4951: 4948: 4947: 4924: 4919: 4916: 4911: 4901: 4897: 4893: 4882: 4878: 4873: 4870: 4861: 4841: 4840: 4827: 4821: 4818: 4816: 4813: 4811: 4808: 4807: 4804: 4801: 4799: 4796: 4794: 4791: 4790: 4788: 4783: 4780: 4777: 4774: 4771: 4768: 4751:rank deficient 4736: 4733: 4724: 4718: 4715: 4710: 4706: 4697: 4692: 4687: 4684: 4656: 4653: 4650: 4647: 4636: 4635: 4622: 4618: 4614: 4607: 4604: 4595: 4588: 4582: 4579: 4574: 4564: 4560: 4556: 4545: 4537: 4517: 4514: 4511: 4508: 4505: 4502: 4499: 4496: 4493: 4482: 4469: 4465: 4461: 4458: 4451: 4448: 4439: 4432: 4422: 4416: 4413: 4408: 4404: 4395: 4390: 4364: 4361: 4358: 4355: 4352: 4349: 4346: 4343: 4340: 4309: 4298:if and only if 4296:is invertible 4285: 4255: 4227: 4204: 4189: 4186: 4153: 4150: 4145: 4142: 4137:Main article: 4134: 4131: 4035: 4034: 4006: 3961:; this endows 3942: 3936: 3911: 3899: 3887: 3880: 3685:Main article: 3682: 3681:In a semigroup 3679: 3674: 3659: 3656: 3653: 3650: 3630: 3619:group of units 3594: 3578: 3577: 3574: 3571: 3568: 3565: 3562: 3558: 3557: 3554: 3551: 3548: 3545: 3542: 3538: 3537: 3534: 3531: 3528: 3525: 3522: 3518: 3517: 3514: 3511: 3508: 3505: 3502: 3498: 3497: 3494: 3491: 3488: 3485: 3482: 3478: 3477: 3474: 3471: 3468: 3465: 3462: 3437: 3434: 3431: 3428: 3425: 3412: 3411: 3408: 3405: 3402: 3398: 3397: 3394: 3391: 3388: 3384: 3383: 3380: 3377: 3374: 3370: 3369: 3366: 3363: 3360: 3339: 3336: 3333: 3330: 3327: 3307: 3306: 3303: 3300: 3297: 3293: 3292: 3289: 3286: 3283: 3279: 3278: 3275: 3272: 3269: 3265: 3264: 3261: 3258: 3255: 3237: 3234: 3231: 3228: 3225: 3194: 3170: 3150: 3122: 3102: 3082: 3062: 3038: 3018: 2994: 2974: 2971: 2968: 2965: 2962: 2942: 2939: 2936: 2933: 2930: 2910: 2907: 2904: 2881: 2850: 2838: 2835: 2833: 2830: 2759: 2756: 2753: 2750: 2745: 2741: 2706: 2674: 2650: 2646: 2643: 2639: 2636: 2616: 2613: 2609: 2606: 2585: 2582: 2579: 2559: 2556: 2553: 2549: 2546: 2542: 2539: 2519: 2516: 2513: 2510: 2507: 2458: 2455: 2412:inverse matrix 2357:is defined if 2339:columns), and 2304:are considered 2272: 2269: 2177: 2172: 2169: 2147: 2142: 2139: 2135: 2075:, and denoted 2054:multiplication 2037: 2034: 1983: 1980: 1977: 1956: 1953: 1950: 1947: 1944: 1924: 1921: 1918: 1915: 1895: 1892: 1889: 1886: 1883: 1830:group of units 1791: 1788: 1769: 1766: 1746: 1743: 1723: 1701: 1698: 1694: 1643: 1640: 1618:An invertible 1605: 1600: 1597: 1593: 1587: 1584: 1580: 1559: 1556: 1553: 1533: 1530: 1527: 1490: 1487: 1459: 1456: 1453: 1449: 1428: 1423: 1420: 1417: 1413: 1392: 1387: 1384: 1358: 1353: 1350: 1346: 1321: 1318: 1315: 1290: 1289: 1278: 1275: 1272: 1269: 1266: 1263: 1260: 1257: 1254: 1251: 1248: 1245: 1242: 1239: 1236: 1233: 1230: 1227: 1224: 1221: 1190:An element is 1187: 1184: 1137: 1132: 1128: 1125: 1122: 1097: 1094: 1077:floor function 1064: 1060: 1055: 1052: 1047: 1043: 1040: 1020: 1017: 1014: 1011: 991: 988: 960: 957: 954: 951: 866: 863: 860: 857: 854: 851: 839: 836: 788: 785: 782: 751: 748: 745: 742: 739: 736: 733: 730: 710: 707: 704: 701: 681: 678: 675: 645: 644: 633: 630: 627: 624: 621: 611: 608: 605: 602: 599: 583:is an element 562:be a possibly 551: 539: 536: 503: 502: 491: 488: 485: 482: 479: 476: 473: 470: 467: 464: 461: 458: 455: 452: 449: 430: 427: 415: 412: 341: 338: 307: 304: 278: 275: 179:or simply the 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 5913: 5902: 5899: 5897: 5894: 5892: 5889: 5888: 5886: 5876: 5872: 5869: 5865: 5861: 5858: 5854: 5849: 5847:0-19-851194-9 5843: 5839: 5835: 5830: 5827: 5826:3-11-015248-7 5823: 5819: 5815: 5814: 5810: 5801: 5795: 5792: 5786: 5783: 5777: 5774: 5770: 5766: 5762: 5758: 5752: 5749: 5742: 5738: 5735: 5733: 5730: 5728: 5725: 5723: 5722:Division ring 5720: 5719: 5715: 5713: 5711: 5690: 5684: 5679: 5674: 5667: 5662: 5657: 5650: 5645: 5640: 5634: 5629: 5624: 5618: 5613: 5608: 5601: 5596: 5591: 5585: 5578: 5572: 5567: 5560: 5555: 5548: 5543: 5537: 5532: 5529: 5520: 5512: 5511: 5510: 5487: 5484: 5475: 5471: 5466: 5460: 5457: 5452: 5445: 5440: 5437: 5430: 5425: 5422: 5416: 5409: 5406: 5401: 5396: 5390: 5385: 5382: 5375: 5372: 5367: 5361: 5354: 5348: 5343: 5336: 5331: 5324: 5319: 5313: 5306: 5303: 5298: 5296: 5289: 5286: 5281: 5271: 5267: 5263: 5252: 5242: 5236: 5231: 5228: 5221: 5218: 5213: 5207: 5200: 5197: 5192: 5187: 5184: 5178: 5172: 5167: 5160: 5155: 5149: 5143: 5141: 5134: 5131: 5126: 5116: 5112: 5108: 5097: 5091: 5086: 5079: 5074: 5068: 5063: 5058: 5052: 5047: 5040: 5035: 5028: 5023: 5017: 5010: 5004: 4999: 4994: 4987: 4982: 4977: 4971: 4966: 4964: 4953: 4949: 4938: 4937: 4936: 4922: 4917: 4914: 4909: 4899: 4895: 4891: 4880: 4876: 4871: 4868: 4859: 4850: 4846: 4825: 4819: 4814: 4809: 4802: 4797: 4792: 4786: 4781: 4778: 4775: 4772: 4769: 4766: 4759: 4758: 4757: 4754: 4752: 4747: 4734: 4731: 4722: 4716: 4713: 4708: 4704: 4695: 4690: 4685: 4682: 4674: 4670: 4669:least squares 4654: 4651: 4648: 4645: 4620: 4616: 4612: 4605: 4602: 4593: 4586: 4580: 4577: 4572: 4562: 4558: 4554: 4543: 4535: 4515: 4512: 4509: 4506: 4503: 4500: 4497: 4494: 4491: 4483: 4467: 4463: 4459: 4456: 4449: 4446: 4437: 4430: 4420: 4414: 4411: 4406: 4402: 4393: 4388: 4362: 4359: 4356: 4353: 4350: 4347: 4344: 4341: 4338: 4330: 4329: 4328: 4326: 4321: 4307: 4299: 4283: 4276: 4271: 4269: 4253: 4245: 4241: 4225: 4218: 4202: 4195: 4194:square matrix 4187: 4185: 4183: 4179: 4175: 4171: 4167: 4163: 4159: 4151: 4149: 4143: 4140: 4132: 4130: 4128: 4124: 4120: 4116: 4112: 4108: 4104: 4100: 4096: 4092: 4088: 4084: 4080: 4076: 4072: 4068: 4064: 4060: 4056: 4052: 4048: 4044: 4040: 4032: 4028: 4024: 4020: 4016: 4012: 4011: 4007: 4005: 4001: 3997: 3993: 3991: 3987: 3986: 3985: 3983: 3979: 3975: 3971: 3969: 3964: 3960: 3956: 3952: 3948: 3940: 3937: 3935: 3933: 3929: 3928:quasi-inverse 3924: 3922: 3918: 3910: 3906: 3902: 3898: 3892: 3890: 3883: 3876: 3872: 3868: 3864: 3860: 3856: 3852: 3848: 3844: 3840: 3836: 3832: 3828: 3824: 3820: 3816: 3812: 3808: 3804: 3800: 3796: 3792: 3788: 3784: 3780: 3776: 3772: 3768: 3764: 3760: 3756: 3752: 3748: 3744: 3740: 3737:. An element 3736: 3735: 3734:pseudoinverse 3730: 3726: 3722: 3718: 3714: 3710: 3706: 3702: 3697: 3695: 3688: 3680: 3678: 3673: 3654: 3648: 3628: 3620: 3617:, called the 3616: 3612: 3608: 3592: 3583: 3575: 3572: 3569: 3566: 3563: 3560: 3559: 3555: 3552: 3549: 3546: 3543: 3540: 3539: 3535: 3532: 3529: 3526: 3523: 3520: 3519: 3515: 3512: 3509: 3506: 3503: 3500: 3499: 3495: 3492: 3489: 3486: 3483: 3480: 3479: 3459: 3456: 3453: 3451: 3432: 3429: 3426: 3409: 3406: 3403: 3400: 3399: 3395: 3392: 3389: 3386: 3385: 3381: 3378: 3375: 3372: 3371: 3357: 3354: 3353: 3350:given by the 3334: 3331: 3328: 3317: 3312: 3304: 3301: 3298: 3295: 3294: 3290: 3287: 3284: 3281: 3280: 3276: 3273: 3270: 3267: 3266: 3252: 3249: 3232: 3229: 3226: 3214: 3212: 3208: 3192: 3184: 3168: 3148: 3140: 3136: 3120: 3100: 3080: 3060: 3052: 3051:right inverse 3036: 3016: 3008: 2992: 2972: 2969: 2966: 2963: 2960: 2940: 2937: 2934: 2931: 2928: 2908: 2905: 2902: 2895: 2879: 2872: 2868: 2865:, that is, a 2864: 2848: 2836: 2831: 2829: 2827: 2823: 2819: 2815: 2814:vector spaces 2811: 2807: 2802: 2800: 2796: 2792: 2787: 2785: 2781: 2777: 2757: 2751: 2748: 2743: 2739: 2731: 2726: 2720: 2704: 2696: 2688: 2672: 2664: 2648: 2644: 2641: 2637: 2634: 2614: 2611: 2607: 2604: 2583: 2580: 2577: 2557: 2554: 2547: 2544: 2540: 2537: 2517: 2511: 2508: 2505: 2496: 2494: 2489: 2487: 2483: 2479: 2475: 2471: 2470:homomorphisms 2467: 2463: 2456: 2454: 2450: 2440: 2436: 2432: 2427: 2419: 2417: 2416:Cramer's rule 2413: 2401: 2393: 2388: 2378: 2377:main diagonal 2374: 2373:square matrix 2370: 2365: 2361: 2351: 2347: 2329: 2325: 2315: 2313: 2309: 2305: 2303: 2297: 2293: 2289: 2285: 2281: 2277: 2270: 2268: 2266: 2262: 2258: 2254: 2250: 2242: 2241:zero divisors 2238: 2233: 2231: 2227: 2223: 2218: 2216: 2215:division ring 2212: 2203: 2197: 2188: 2175: 2170: 2167: 2145: 2140: 2137: 2133: 2120: 2116: 2112: 2104: 2100: 2095: 2092: 2087:and denoted 2086: 2074: 2070: 2066: 2062: 2061:abelian group 2057: 2055: 2051: 2047: 2043: 2035: 2033: 2031: 2027: 2026:localizations 2023: 2019: 2015: 2011: 2007: 2003: 1999: 1981: 1978: 1975: 1954: 1951: 1948: 1945: 1942: 1922: 1919: 1916: 1913: 1893: 1890: 1887: 1884: 1881: 1869: 1863: 1861: 1857: 1853: 1849: 1845: 1840: 1838: 1833: 1832:of the ring. 1831: 1828:and form the 1827: 1823: 1818: 1816: 1812: 1807: 1805: 1801: 1797: 1789: 1787: 1785: 1780: 1767: 1764: 1744: 1741: 1721: 1699: 1696: 1692: 1683: 1679: 1674: 1672: 1668: 1664: 1659: 1657: 1653: 1649: 1641: 1639: 1637: 1633: 1629: 1625: 1622:is called an 1621: 1616: 1603: 1598: 1595: 1591: 1585: 1582: 1578: 1557: 1554: 1551: 1531: 1528: 1525: 1508: 1506: 1488: 1485: 1475: 1457: 1454: 1451: 1447: 1439:The notation 1426: 1421: 1418: 1415: 1411: 1390: 1385: 1382: 1372: 1356: 1351: 1348: 1344: 1319: 1316: 1313: 1301: 1296: 1294: 1276: 1273: 1270: 1267: 1264: 1258: 1255: 1252: 1246: 1240: 1237: 1234: 1228: 1225: 1222: 1219: 1212: 1211: 1210: 1195: 1193: 1185: 1183: 1181: 1177: 1173: 1168: 1166: 1162: 1158: 1153: 1135: 1130: 1126: 1123: 1120: 1095: 1092: 1078: 1062: 1058: 1053: 1050: 1045: 1038: 1018: 1015: 1012: 1009: 989: 986: 974: 958: 955: 949: 942: 938: 933: 931: 927: 919: 911: 906: 900: 899:right inverse 888: 864: 861: 858: 855: 852: 849: 837: 835: 833: 829: 824: 818: 814: 810: 805: 800: 786: 783: 780: 763: 749: 746: 743: 740: 737: 734: 731: 728: 708: 705: 702: 699: 679: 676: 673: 656: 631: 628: 625: 622: 619: 609: 606: 603: 600: 597: 590: 589: 588: 582: 578: 577: 571: 565: 549: 537: 535: 533: 529: 524: 517: 513: 509: 489: 486: 480: 477: 474: 468: 462: 459: 456: 450: 447: 440: 439: 438: 436: 429:Associativity 428: 426: 413: 410: 402: 398: 389: 387: 383: 382:associativity 379: 375: 371: 367: 363: 359: 355: 351: 347: 339: 335: 331: 327: 322: 305: 302: 276: 273: 262: 258: 257: 252: 247: 245: 241: 237: 233: 229: 225: 221: 217: 212: 210: 206: 202: 198: 194: 190: 186: 182: 178: 170: 161: 150: 146: 142: 136: 132: 128: 119: 118:right inverse 107: 98: 94: 90: 81: 74:denoted here 73: 68: 65: 59: 54: 48: 44: 40: 33: 19: 5863: 5856: 5833: 5817: 5794: 5789:Howie p. 102 5785: 5776: 5751: 5707: 5508: 4848: 4844: 4842: 4755: 4748: 4671:formula for 4637: 4322: 4272: 4191: 4181: 4177: 4173: 4169: 4165: 4161: 4155: 4147: 4126: 4122: 4118: 4114: 4110: 4106: 4102: 4098: 4094: 4090: 4086: 4082: 4078: 4062: 4058: 4054: 4050: 4046: 4045:; these are 4038: 4036: 4030: 4022: 4018: 4014: 4010:*-semigroups 4008: 4003: 3999: 3995: 3989: 3988: 3981: 3977: 3973: 3967: 3966: 3962: 3958: 3954: 3950: 3946: 3944: 3938: 3927: 3925: 3908: 3904: 3896: 3893: 3885: 3878: 3874: 3866: 3862: 3858: 3854: 3850: 3846: 3842: 3838: 3834: 3830: 3826: 3822: 3818: 3814: 3806: 3802: 3798: 3794: 3790: 3786: 3782: 3778: 3774: 3770: 3766: 3762: 3758: 3754: 3750: 3746: 3742: 3738: 3732: 3728: 3724: 3720: 3716: 3712: 3708: 3704: 3700: 3698: 3690: 3671: 3584: 3581: 3454: 3450:Latin square 3415: 3352:Cayley table 3313: 3310: 3215: 3210: 3206: 3182: 3138: 3134: 3133:is called a 3050: 3049:is called a 3007:left inverse 3006: 3005:is called a 2861:be a unital 2840: 2816:but not for 2803: 2798: 2788: 2729: 2728:There is an 2727: 2497: 2490: 2485: 2460: 2451: 2439:real numbers 2428: 2420: 2389: 2363: 2359: 2349: 2345: 2327: 2323: 2316: 2299: 2274: 2249:localization 2234: 2219: 2204: 2198:, which has 2189: 2110: 2105:and denoted 2096: 2090: 2058: 2053: 2049: 2039: 1870:(an element 1864: 1841: 1834: 1819: 1810: 1808: 1802:that has an 1793: 1781: 1680:on a set as 1676:A group may 1675: 1660: 1645: 1620:homomorphism 1617: 1509: 1297: 1292: 1291: 1196: 1191: 1189: 1169: 1154: 940: 934: 912:, which has 907: 898: 887:left inverse 886: 841: 825: 812: 808: 801: 764: 657: 646: 580: 574: 572: 541: 525: 515: 511: 507: 504: 432: 401:proper class 399:(possibly a 390: 349: 345: 343: 248: 213: 204: 196: 180: 176: 162: 148: 144: 140: 134: 130: 126: 117: 106:left inverse 105: 96: 92: 88: 69: 63: 52: 42: 36: 5708:which is a 4244:determinant 3992:-semigroups 3941:-semigroups 3811:idempotents 3703:an element 3607:associative 2717:equals the 2493:associative 2486:composition 2462:Composition 2312:determinant 2298:. However, 2232:to itself. 2217:otherwise. 2125:is denoted 2069:associative 2065:commutative 1837:commutative 1636:isomorphism 1624:isomorphism 1371:commutative 1306:is denoted 1293:The inverse 1180:retractions 826:Similarly, 587:such that 435:associative 326:associative 240:isomorphism 169:associative 112:, and that 39:mathematics 5885:Categories 5811:References 4673:regression 4270:for more. 4089:such that 4027:involution 3970:-semigroup 3813:, that is 3719:such that 3707:is called 3183:invertible 3181:is called 2953:, we have 2921:. If, for 2810:surjective 2482:categories 1790:In monoids 1671:involution 1192:invertible 1165:surjective 1079:that maps 979:to either 647:for every 505:for every 58:reciprocal 5485:− 5458:− 5438:− 5423:− 5383:− 5373:− 5287:− 5229:− 5219:− 5185:− 5132:− 4915:− 4869:− 4776:× 4714:− 4603:− 4587:⏟ 4578:− 4507:∣ 4501:× 4447:− 4431:⏟ 4412:− 4354:∣ 4348:× 4325:full rank 4133:Semirings 3694:semigroup 3593:∗ 3433:∗ 3335:∗ 3233:∗ 2964:∗ 2938:∈ 2906:∈ 2880:∗ 2806:injective 2791:bijection 2755:→ 2749:: 2638:⊂ 2581:∘ 2552:→ 2541:: 2515:→ 2509:: 2478:morphisms 2335:rows and 2296:semirings 2196:zero ring 2138:− 1844:functions 1697:− 1642:In groups 1596:− 1583:− 1555:∗ 1529:∗ 1455:− 1452:∘ 1419:− 1416:∗ 1349:− 1314:− 1265:∗ 1256:∗ 1238:∗ 1229:∗ 1161:injective 1124:− 1042:↦ 953:↦ 937:functions 853:∗ 784:∗ 738:∗ 677:∗ 623:∗ 601:∗ 550:∗ 487:∗ 478:∗ 460:∗ 451:∗ 411:∗ 374:morphisms 328:and have 261:fractions 78:, and an 72:operation 70:Given an 5716:See also 4144:Examples 3953:for all 3861:, while 2730:identity 2695:codomain 2663:codomain 2645:′ 2608:′ 2548:′ 2280:matrices 2271:Matrices 2050:addition 2036:In rings 2014:integers 2002:integers 1967:implies 1906:implies 1663:function 1654:with an 1632:morphism 1476:, since 1209:, then 1186:Inverses 1176:sections 1059:⌋ 1046:⌊ 581:identity 378:category 256:inversus 244:morphism 152:for all 82:denoted 47:opposite 5891:Algebra 4843:So, as 3743:inverse 3139:inverse 3113:, then 2985:, then 2892:and an 2869:with a 2818:modules 2282:over a 2265:subring 2228:from a 1626:. In 564:partial 181:inverse 5844:  5824:  5763:, and 3949:°)° = 3853:, and 3611:monoid 2780:object 2719:domain 2687:domain 2259:of an 2099:monoid 2044:is an 2024:, and 2020:of an 1796:monoid 920:, and 893:, and 877:where 358:domain 216:groups 191:, and 56:) and 5743:Notes 5480:right 4864:right 4847:< 4598:right 4217:field 4117:)* = 4109:)* = 4105:, ( 4017:)° = 3793:then 3615:group 3141:, of 2863:magma 2824:or a 2464:is a 2343:is a 2321:is a 2288:rings 2284:field 2220:In a 2211:field 2109:. An 2012:from 2004:from 1826:units 1815:group 1667:arity 1650:is a 1648:group 897:is a 885:is a 395:is a 376:in a 251:Latin 224:units 220:rings 203:, an 116:is a 104:is a 86:, if 5842:ISBN 5822:ISBN 4513:< 4484:For 4442:left 4360:> 4331:For 4176:and 4164:and 4053:° = 3821:and 3809:are 3801:and 3757:and 3316:loop 3029:and 2841:Let 2530:and 2476:and 2402:in 2400:unit 2310:and 2308:rank 2294:and 2292:rngs 2115:unit 2067:and 2052:and 2042:ring 1935:and 1822:ring 1809:The 1514:and 1201:and 1075:the 769:and 662:and 651:and 542:Let 437:if 384:and 348:and 230:and 209:unit 201:ring 156:and 138:and 4749:No 4178:GLG 4170:LGL 4125:or 4113:, ( 4099:yxy 4091:xyx 3957:in 3934:). 3779:zxz 3771:xzx 3763:yxy 3751:xyx 3749:if 3745:of 3721:xzx 3715:in 3670:or 3621:of 3605:is 3209:or 3185:in 3053:of 3009:of 2867:set 2808:or 2776:set 2721:of 2697:of 2689:of 2665:of 2498:If 2480:of 2472:of 2445:or 2421:If 2418:. 2390:An 2317:If 2205:If 2028:of 1678:act 1652:set 1510:If 1170:In 1167:. 1110:or 1083:to 1002:or 916:as 901:of 889:of 842:If 658:If 615:and 573:An 519:in 397:set 321:). 292:is 167:is 120:of 108:of 37:In 5887:: 5866:, 5840:. 5836:. 5685:45 5680:36 5675:27 5668:36 5663:29 5658:22 5651:27 5646:22 5641:17 5453:13 5426:17 5410:18 5391:14 5386:32 5376:32 5368:77 5307:54 5237:14 5232:32 5222:32 5214:77 5201:54 5173:77 5168:32 5161:32 5156:14 5092:77 5087:32 5080:32 5075:14 4320:. 4192:A 4180:= 4172:= 4160:, 4129:. 4119:yx 4115:yx 4111:xy 4107:xy 4101:= 4097:, 4093:= 4051:aa 4015:ab 4002:= 3996:aa 3849:= 3847:fy 3845:= 3843:ye 3841:, 3837:= 3835:xf 3833:= 3831:ex 3825:= 3823:ff 3817:= 3815:ee 3807:yx 3805:= 3799:xy 3797:= 3777:= 3769:= 3761:= 3753:= 3727:; 3723:= 3696:. 3677:. 3576:3 3573:2 3570:4 3567:1 3564:5 3561:5 3556:1 3553:3 3550:2 3547:5 3544:4 3541:4 3536:2 3533:1 3530:5 3527:4 3524:3 3521:3 3516:4 3513:5 3510:1 3507:3 3504:2 3501:2 3496:5 3493:4 3490:3 3487:2 3484:1 3481:1 3476:5 3473:4 3470:3 3467:2 3464:1 3461:* 3452:. 3410:1 3407:2 3404:3 3401:3 3396:2 3393:1 3390:2 3387:2 3382:3 3379:2 3376:1 3373:1 3368:3 3365:2 3362:1 3359:* 3305:1 3302:1 3299:3 3296:3 3291:1 3288:1 3285:2 3282:2 3277:3 3274:2 3271:1 3268:1 3263:3 3260:2 3257:1 3254:* 3213:. 2801:. 2740:id 2725:. 2495:. 2447:−1 2387:. 2362:= 2355:AB 2314:. 2290:, 2235:A 2040:A 2032:. 2008:, 1994:). 1862:. 1820:A 1806:. 1794:A 1646:A 1638:. 1507:. 1182:. 905:. 762:) 570:. 534:. 514:, 510:, 368:, 253:: 246:. 187:, 147:= 143:* 133:= 129:* 95:= 91:∗ 62:1/ 5850:. 5802:. 5771:. 5691:] 5635:[ 5630:= 5625:] 5619:6 5614:5 5609:4 5602:3 5597:2 5592:1 5586:[ 5579:] 5573:6 5568:3 5561:5 5556:2 5549:4 5544:1 5538:[ 5533:= 5530:A 5525:T 5521:A 5488:1 5476:A 5472:= 5467:] 5461:4 5446:2 5441:2 5431:8 5417:[ 5407:1 5402:= 5397:] 5362:[ 5355:] 5349:6 5344:3 5337:5 5332:2 5325:4 5320:1 5314:[ 5304:1 5299:= 5290:1 5282:) 5276:T 5272:A 5268:A 5264:( 5257:T 5253:A 5243:] 5208:[ 5198:1 5193:= 5188:1 5179:] 5150:[ 5144:= 5135:1 5127:) 5121:T 5117:A 5113:A 5109:( 5098:] 5069:[ 5064:= 5059:] 5053:6 5048:3 5041:5 5036:2 5029:4 5024:1 5018:[ 5011:] 5005:6 5000:5 4995:4 4988:3 4983:2 4978:1 4972:[ 4967:= 4958:T 4954:A 4950:A 4923:. 4918:1 4910:) 4904:T 4900:A 4896:A 4892:( 4885:T 4881:A 4877:= 4872:1 4860:A 4849:n 4845:m 4826:] 4820:6 4815:5 4810:4 4803:3 4798:2 4793:1 4787:[ 4782:= 4779:3 4773:2 4770:: 4767:A 4735:. 4732:b 4727:T 4723:A 4717:1 4709:) 4705:A 4700:T 4696:A 4691:( 4686:= 4683:x 4655:b 4652:= 4649:x 4646:A 4621:m 4617:I 4613:= 4606:1 4594:A 4581:1 4573:) 4567:T 4563:A 4559:A 4555:( 4548:T 4544:A 4536:A 4516:n 4510:m 4504:n 4498:m 4495:: 4492:A 4468:n 4464:I 4460:= 4457:A 4450:1 4438:A 4425:T 4421:A 4415:1 4407:) 4403:A 4398:T 4394:A 4389:( 4363:n 4357:m 4351:n 4345:m 4342:: 4339:A 4308:R 4284:R 4254:M 4226:K 4203:M 4182:G 4174:L 4166:G 4162:L 4103:y 4095:x 4087:y 4083:x 4079:a 4063:a 4059:a 4057:° 4055:a 4047:I 4039:I 4033:* 4031:a 4023:a 4021:° 4019:b 4004:a 4000:a 3998:° 3990:I 3982:U 3978:a 3974:a 3968:U 3963:S 3959:S 3955:a 3951:a 3947:a 3939:U 3912:e 3909:H 3905:e 3900:1 3897:H 3888:e 3886:L 3881:e 3879:R 3875:e 3867:y 3863:f 3859:x 3855:e 3851:y 3839:x 3827:f 3819:e 3803:f 3795:e 3791:x 3787:y 3783:x 3775:y 3767:x 3759:y 3755:x 3747:x 3739:y 3729:z 3725:x 3717:S 3713:z 3705:x 3701:S 3675:1 3672:H 3658:) 3655:S 3652:( 3649:U 3629:S 3436:) 3430:, 3427:S 3424:( 3338:) 3332:, 3329:S 3326:( 3236:) 3230:, 3227:S 3224:( 3193:S 3169:S 3149:y 3121:x 3101:y 3081:x 3061:a 3037:b 3017:b 2993:a 2973:e 2970:= 2967:b 2961:a 2941:S 2935:b 2932:, 2929:a 2909:S 2903:e 2849:S 2774:( 2772:X 2758:X 2752:X 2744:X 2723:g 2705:f 2691:g 2673:f 2649:. 2642:Y 2635:Y 2615:Y 2612:= 2605:Y 2584:f 2578:g 2558:, 2555:Z 2545:Y 2538:g 2518:Y 2512:X 2506:f 2443:1 2423:R 2408:R 2404:R 2396:R 2385:0 2381:1 2364:p 2360:n 2350:q 2348:× 2346:p 2341:B 2337:n 2333:m 2328:n 2326:× 2324:m 2319:A 2245:0 2207:0 2200:0 2192:0 2176:. 2171:x 2168:1 2146:, 2141:1 2134:x 2123:x 2107:1 2091:x 2089:− 2081:x 2077:0 1982:z 1979:= 1976:y 1955:x 1952:z 1949:= 1946:x 1943:y 1923:, 1920:z 1917:= 1914:y 1894:z 1891:x 1888:= 1885:y 1882:x 1872:x 1768:. 1765:g 1745:, 1742:g 1722:g 1700:1 1693:g 1604:. 1599:1 1592:x 1586:1 1579:y 1558:y 1552:x 1532:y 1526:x 1516:y 1512:x 1489:f 1486:1 1458:1 1448:f 1427:. 1422:1 1412:x 1391:. 1386:x 1383:1 1357:, 1352:1 1345:x 1334:x 1320:. 1317:x 1304:x 1277:. 1274:r 1271:= 1268:r 1262:) 1259:x 1253:l 1250:( 1247:= 1244:) 1241:r 1235:x 1232:( 1226:l 1223:= 1220:l 1207:x 1203:r 1199:l 1150:n 1136:, 1131:2 1127:1 1121:n 1096:2 1093:n 1081:n 1063:, 1054:2 1051:n 1039:n 1019:1 1016:+ 1013:n 1010:2 990:n 987:2 977:n 959:x 956:2 950:x 922:0 914:0 903:x 895:y 891:y 883:x 879:e 865:, 862:e 859:= 856:y 850:x 821:n 813:n 811:× 809:n 787:f 781:e 771:f 767:e 750:. 747:f 744:= 741:f 735:e 732:= 729:e 709:. 706:f 703:= 700:e 680:f 674:e 664:f 660:e 653:y 649:x 632:y 629:= 626:y 620:e 610:x 607:= 604:e 598:x 585:e 568:X 521:X 516:z 512:y 508:x 490:z 484:) 481:y 475:x 472:( 469:= 466:) 463:z 457:y 454:( 448:x 414:. 393:X 336:. 306:x 303:y 277:y 274:x 173:x 165:∗ 158:y 154:x 149:y 145:y 141:e 135:x 131:e 127:x 122:x 114:y 110:y 102:x 97:e 93:y 89:x 84:e 76:∗ 64:x 60:( 53:x 51:− 49:( 34:. 20:)

Index

Inverse (ring theory)
Invertible (disambiguation)
mathematics
opposite
reciprocal
operation
identity element
associative
additive inverse
multiplicative inverse
functional inverse
ring
unit
groups
rings
units
inverse matrices
inverse functions
category theory
isomorphism
morphism
Latin
inversus
fractions
associative
identity elements
§ Generalizations
binary operations
domain
partial operations

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