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Semigroup

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31: 3285: 1084:. A semigroup may have at most one two-sided identity. If a semigroup has a two-sided identity, then the two-sided identity is the only one-sided identity in the semigroup. If a semigroup has both a left identity and a right identity, then it has a two-sided identity (which is therefore the unique one-sided identity). 4560:, the semigroups based on multiplication modulo 2 (choosing a or b as the identity element 1), the groups equivalent to addition modulo 2 (choosing a or b to be the identity element 0), and the semigroups in which the elements are either both left identities or both right identities. 248:
do form a monoid. A semigroup without an identity element can be easily turned into a monoid by just adding an identity element. Consequently, monoids are studied in the theory of semigroups rather than in group theory. Semigroups should not be confused with
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and at least one idempotent. The number of finite semigroups of a given size (greater than 1) is (obviously) larger than the number of groups of the same size. For example, of the sixteen possible "multiplication tables" for a set of two elements
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obtained the first non-trivial results about semigroups. His 1928 paper "Über die endlichen Gruppen ohne das Gesetz der eindeutigen Umkehrbarkeit" ("On finite groups without the rule of unique invertibility") determined the structure of finite
3458: 3582: 326:, semigroups with additional properties, which appear in particular applications. Some of these classes are even closer to groups by exhibiting some additional but not all properties of a group. Of these we mention: 2074:. There is a close relationship between the subgroups of a semigroup and its idempotents. Each subgroup contains exactly one idempotent, namely the identity element of the subgroup. For each idempotent 4529:
The closure axiom is implied by the definition of a binary operation on a set. Some authors thus omit it and specify three axioms for a group and only one axiom (associativity) for a semigroup.
4448:, in which the requirement that the binary relation be total is lifted. As categories generalize monoids in the same way, a semigroupoid behaves much like a category but lacks identities. 3280:{\displaystyle {\begin{cases}\partial _{t}u(t,x)=\partial _{x}^{2}u(t,x),&x\in (0,1),t>0;\\u(t,x)=0,&x\in \{0,1\},t>0;\\u(t,x)=u_{0}(x),&x\in (0,1),t=0.\end{cases}}} 2624:
Whenever we take the quotient of a commutative semigroup by a congruence, we get another commutative semigroup. The structure theorem says that for any commutative semigroup
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of the semigroup provides a construction of the group of fractions. The problem for non-commutative semigroups can be traced to the first substantial paper on semigroups.
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are regular semigroups where every element has exactly one inverse. Alternatively, a regular semigroup is inverse if and only if any two idempotents commute.
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In recent years researchers in the field have become more specialized with dedicated monographs appearing on important classes of semigroups, like
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An important question is to characterize those semigroups for which this map is an embedding. This need not always be the case: for example, take
3471:. Then the above initial/boundary value problem can be interpreted as an initial value problem for an ordinary differential equation on the space 3481: 4853: 2100:}, eight form semigroups whereas only four of these are monoids and only two form groups. For more on the structure of finite semigroups, see 177:, without requiring the existence of an identity element or inverses. As in the case of groups or magmas, the semigroup operation need not be 5515: 5485: 5466: 5436: 5280: 5253: 5215: 5195: 5166: 5145: 5105: 5069: 4810: 4785: 4693: 4658: 2082:. Each maximal subgroup arises in this way, so there is a one-to-one correspondence between idempotents and maximal subgroups. Here the term 359: 272:, in which arbitrary functions replace the role of bijections in group theory. A deep result in the classification of finite semigroups is 5017: 277: 5347: 3741:. The latter two published a two-volume monograph on semigroup theory in 1961 and 1967 respectively. In 1970, a new periodical called 686: 253:, which are generalization of groups in a different direction; the operation in a quasigroup need not be associative but quasigroups 93:
The binary operation of a semigroup is most often denoted multiplicatively (just notation, not necessarily the elementary arithmetic
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Affine semigroup: a semigroup that is isomorphic to a finitely-generated subsemigroup of Z. These semigroups have applications to
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Monoids, Acts, and Categories: With Applications to Wreath Products and Graphs : a Handbook for Students and Researchers
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More can often be said when the order is finite. For example, every nonempty finite semigroup is periodic, and has a minimal
316: 228:, thus obeying all but one of the axioms of a group: existence of inverses is not required of a monoid. A natural example is 5548: 5339: 5137: 4490: 2665: 2115: 861: 679: 323: 1783:
of any semigroup homomorphism is a semigroup congruence. These results are nothing more than a particularization of the
312: 288: 4577:, in M. Hazewinkel, Handbook of Algebra, Vol. 1, Elsevier, 1996. Notice that in this context the authors use the term 3714:
J-class) of a finite semigroup is simple. From that point on, the foundations of semigroup theory were further laid by
1458:. But there are semigroup homomorphisms that are not monoid homomorphisms, e.g. the canonical embedding of a semigroup 1345:
An example of a semigroup with no minimal ideal is the set of positive integers under addition. The minimal ideal of a
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B. M. Schein & R. McKenzie (1997) "Every semigroup is isomorphic to a transitive semigroup of binary relations",
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The subset with the property that every element commutes with any other element of the semigroup is called the
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they generate, are important tools for analysing the ideals of a semigroup and related notions of structure.
4959: 3695:(Elements of the Theory of Abstract Groups) in 1904. The term is used in English in 1908 in Harold Hinton's 2801: 1788: 639: 3683:
The study of semigroups trailed behind that of other algebraic structures with more complex axioms such as
3890: 2980: 2151: 967: 723: 343: 258: 1078:) is an element that is both a left and right identity. Semigroups with a two-sided identity are called 5370: 5057: 4451:
Infinitary generalizations of commutative semigroups have sometimes been considered by various authors.
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instead of a binary operation. The associative law is generalized as follows: ternary associativity is
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Because ~ is a congruence, the set of all congruence classes of ~ forms a semigroup with ∘, called the
1447:, i.e. the result is the same when performing the semigroup operation after or before applying the map 3839: 3824: 3711: 3321: 2455: 2321: 2313: 1784: 1619: 1356: 1352: 741: 626: 618: 590: 585: 576: 533: 475: 281: 51: 4859: 3490: 3011: 2049:
if all of its elements are of finite order. A semigroup generated by a single element is said to be
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is an algebraic structure intermediate between semigroups and groups, and is a semigroup having an
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for the semigroup product. At an algebraic conference in 1972 Schein surveyed the literature on B
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on a function space. For example, consider the following initial/boundary value problem for the
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with the operation of addition. If it is finite and nonempty, then it must contain at least one
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as the binary operation, and the empty string as the identity element. Restricting to non-empty
5511: 5510:. Encyclopedia of Mathematics and Its Applications. Vol. 90. Cambridge University Press. 5481: 5462: 5432: 5397: 5343: 5276: 5249: 5191: 5162: 5141: 5101: 5065: 4806: 4781: 4689: 4654: 4470: 4460: 4434:
adjacent elements bracketed. A 2-ary semigroup is just a semigroup. Further axioms lead to an
3792: 2405: 2363: 2204:. Every group is a cancellative semigroup, and every finite cancellative semigroup is a group. 1684: 1172: 959: 955: 930: 712: 339: 327: 79: 5213:
Hollings, Christopher (2009). "The Early Development of the Algebraic Theory of Semigroups".
4683: 4648: 3691:. A number of sources attribute the first use of the term (in French) to J.-A. de Séguier in 1199:
The semigroup operation induces an operation on the collection of its subsets: given subsets
346:. There are also interesting classes of semigroups that do not contain any groups except the 5521: 5491: 5442: 5426: 5387: 5379: 5365: 5286: 5259: 5224: 5201: 5172: 5111: 5075: 5033: 4958:
B. M. Schein (1963) "Representations of semigroups by means of binary relations" (Russian),
4892: 4664: 4495: 4485: 4326: 3846: 3829: 3707: 3702: 2126: 2084: 2054: 1368: 1339: 719: 470: 319:, a semigroup is associated to any equation whose spatial evolution is independent of time. 296: 225: 87: 63: 5409: 5357: 5317: 5004: 4985: 4966: 2057:). If a monogenic semigroup is infinite then it is isomorphic to the semigroup of positive 1067:. A semigroup may have one or more left identities but no right identity, and vice versa. 882:
with minimum or maximum. (With positive/negative infinity included, this becomes a monoid.)
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with addition form a commutative semigroup that is not a monoid, whereas the non-negative
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proved that every semigroup is isomorphic to a transitive semigroup of binary relations.
3453:{\displaystyle D(A)={\big \{}u\in H^{2}((0,1);\mathbf {R} ){\big |}u(0)=u(1)=0{\big \}},} 1822: 4942: 5305: 5127: 5091: 4849: 4505: 4115: 4092: 3785: 3738: 3728: 3688: 3609: 2332: 2208: 1884:
The following notions introduce the idea that a semigroup is contained in another one.
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The formal study of semigroups began in the early 20th century. Early results include
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Mathematics across the Iron Curtain: A History of the Algebraic Theory of Semigroups
3751:) became one of the few mathematical journals devoted entirely to semigroup theory. 1713:
and the semigroup operation induces a binary operation ∘ on the congruence classes:
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The Archimedean property follows immediately from the ordering in the semilattice
201:; a well-known example of an operation that is associative but non-commutative is 5333: 5185: 5156: 5131: 5095: 2065:. It follows that every nonempty periodic semigroup has at least one idempotent. 5503: 5325: 4435: 2473: 2425: 2219: 1927:, using the morphism consisting of taking the remainder modulo 2 of an integer. 1589: 1346: 916: 830: 654: 649: 538: 528: 502: 495: 355: 83: 17: 5392: 5228: 4206: 4183: 4025: 4002: 2212: 2062: 1763: 1573: 893: 404: 250: 30: 5401: 2632:
by this equivalence relation is a semilattice. Denoting this semilattice by
2317: 1594: 1466:. Conditions characterizing monoid homomorphisms are discussed further. Let 1326:
is a semigroup, then the intersection of any collection of subsemigroups of
1092: 937:, with convolution as the operation. This is called a convolution semigroup. 813: 659: 465: 422: 205:. If the semigroup operation is commutative, then the semigroup is called a 27:
Algebraic structure consisting of a set with an associative binary operation
3577:{\displaystyle {\begin{cases}{\dot {u}}(t)=Au(t);\\u(0)=u_{0}.\end{cases}}} 864:
representing the three operations on a switch – set, reset, and do nothing.
2621:. This equivalence relation is a semigroup congruence, as defined above. 291:
since the 1950s because of the natural link between finite semigroups and
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of the semigroup. The center of a semigroup is actually a subsemigroup.
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holds: there is no infinite strictly ascending chain of congruences on
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A semigroup homomorphism between monoids preserves identity if it is a
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for finite groups. Some other techniques for studying semigroups, like
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If the associativity axiom of a semigroup is dropped, the result is a
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as the binary operation (this is an example of a semilattice). Since
4228: 3608:. However, for a rigorous treatment, a meaning must be given to the 2312:. Sequencing clearly is an associative operation, here equivalent to 2144: 2122: 1787:. Congruence classes and factor monoids are the objects of study in 1080: 872: 394: 287:
The theory of finite semigroups has been of particular importance in
261:. Division in semigroups (or in monoids) is not possible in general. 221: 55: 3312:
of square-integrable real-valued functions with domain the interval
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Semigroup theory can be used to study some problems in the field of
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gave necessary and sufficient conditions for embeddability in 1937.
2668:. An Archimedean semigroup is one where given any pair of elements 2424:
There is a structure theorem for commutative semigroups in terms of
1964:, while it is not necessarily the case that there are a quotient of 915:
over Σ". With the empty string included, this semigroup becomes the
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that is compatible with the semigroup operation. That is, a subset
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On an heuristic level, the solution to this problem "ought" to be
1683:. Like any equivalence relation, a semigroup congruence ~ induces 827: 29: 2884:
as the "most general" group that contains a homomorphic image of
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from an arbitrary semigroup to a semilattice, each inverse image
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to itself with composition of functions forms a monoid with the
173:, where the operation is associative, or as a generalization of 111:, denotes the result of applying the semigroup operation to the 2078:
of the semigroup there is a unique maximal subgroup containing
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gives an example of a semigroup that is not a monoid. Positive
4883:(1937). "On the immersion of an algebraic ring into a field". 1775:
is a monoid then quotient semigroup is a monoid with identity
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is a function that preserves semigroup structure. A function
4936:"An account of Suschkewitsch's paper by Christopher Hollings" 2147:
of a semigroup that is closed under the semigroup operation.
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is both a left ideal and a right ideal then it is called an
3570: 3273: 2628:, there is a finest congruence ~ such that the quotient of 1179:. Analogous to the above construction, for every semigroup 5310:
An introduction to probability theory and its applications
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See references in Udo Hebisch and Hanns Joachim Weinert,
4919:"Earliest Known Uses of Some of the Words of Mathematics" 4855:
Personal reminiscences of the early history of semigroups
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is commutative this condition is also sufficient and the
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between two semigroups is a homomorphism if the equation
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can be represented by transformations of a (state-) set
826:: there is essentially only one (specifically, only one 4647:
Kilp, Mati; Knauer, U.; Mikhalev, Aleksandr V. (2000).
2428:. A semilattice (or more precisely a meet-semilattice) 911:
of strings as the semigroup operation – the so-called "
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Inverse semigroups: the theory of partial symmetries
4627: 4625: 3795:, as well as monographs focusing on applications in 5158:
Semigroups: An Introduction to the Structure Theory
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Problems on mapping class groups and related topics
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Semigroup methods in partial differential equations
2331:is in fact a monoid, which can be described as the 1821:, ordered by inclusion, has a maximal element. By 3576: 3452: 3279: 2933:. It is clearly necessary for embeddability that 4998:Transactions of the American Mathematical Society 2222:is a semigroup whose operation is idempotent and 1895:if there is a surjective semigroup morphism from 1611:. Isomorphic semigroups have the same structure. 4538:Namely: the trivial semigroup in which (for all 3799:, particularly for finite automata, and also in 2068:A subsemigroup that is also a group is called a 1802:is one that is the kernel of an endomorphism of 871:with addition. (With 0 included, this becomes a 857:: there are five that are essentially different. 4825: 4752: 2472:into a semigroup that satisfies the additional 2088:differs from its standard use in group theory. 1840:of a semigroup induces a factor semigroup, the 1359:that characterise the elements in terms of the 796:More succinctly, a semigroup is an associative 169:Semigroups may be considered a special case of 5100:. Vol. 1. American Mathematical Society. 4368:) is a generalization of a semigroup to a set 2804:. There is an obvious semigroup homomorphism 1785:first isomorphism theorem in universal algebra 126:. Associativity is formally expressed as that 4837: 3442: 3402: 3350: 687: 8: 4415:with any three adjacent elements bracketed. 3693:Élements de la Théorie des Groupes Abstraits 3170: 3158: 2529:is a (possibly empty) semigroup. Moreover, 2420:Structure theorem for commutative semigroups 1063:. Left and right identities are both called 962:acting as the identity. More generally, the 284:, do not resemble anything in group theory. 4930: 4928: 4736:Mathematical Foundations of Automata Theory 2895:to be the semigroup of subsets of some set 2827:to the corresponding generator. This has a 1568:is a monoid homomorphism. Particularly, if 1095:in a monoid formed by adjoining an element 889:of a given size with matrix multiplication. 4346:Generalizing in a different direction, an 3810: 2921:, this must be true for all generators of 2136:is a monoid in which every element has an 1526:is also a monoid with an identity element 1515:) is the identity element in the image of 1486:be a semigroup homomorphism. The image of 694: 680: 364: 5391: 4688:. American Mathematical Soc. p. 96. 4419:-ary associativity is a string of length 3558: 3494: 3493: 3485: 3483: 3441: 3440: 3401: 3400: 3392: 3365: 3349: 3348: 3331: 3217: 3054: 3049: 3018: 3006: 3004: 4801:Auslander, M.; Buchsbaum, D. A. (1974). 4720: 4708: 4616: 2592:by the equivalence relation ~ such that 2402:are sometimes called "mutually inverse". 1971:Both of those relations are transitive. 1825:, this is equivalent to saying that the 1756:is a semigroup homomorphism, called the 1253:.) In terms of this operation, a subset 1175:, which in semigroup theory is called a 311:, semigroups are fundamental models for 4764: 4598: 4522: 3758:of semigroups was developed in 1963 by 3320:be the second-derivative operator with 2316:. This representation is basic for any 1349:semigroup, when it exists, is a group. 1249:(This notion is defined identically as 1171:Similarly, every magma has at most one 367: 5312:. Vol. II (2nd ed.). Wiley. 4631: 4605: 3710:and showed that the minimal ideal (or 5461:. Vol. 1 (2nd ed.). Dover. 5216:Archive for History of Exact Sciences 1497:is a monoid with an identity element 7: 4733:Pin, Jean-Éric (November 30, 2016). 3628:to itself, taking the initial state 2652:becomes graded by this semilattice. 1633:that is an equivalence relation and 1576:, then it is a monoid homomorphism. 900:with the multiplication of the ring. 5335:Functional analysis and semi-groups 4321:, which is nothing more than a set 3624:) is a semigroup of operators from 2704:, since with this ordering we have 5133:The algebraic theory of semigroups 5097:The Algebraic Theory of Semigroups 4979:Miniconference on semigroup Theory 3046: 3015: 2929:) as well, which is therefore the 2211:is a semigroup whose operation is 1956:. In particular, subsemigroups of 1844:, via the congruence ρ defined by 350:; examples of the latter kind are 25: 5248:. American Mathematical Society. 4653:. Walter de Gruyter. p. 25. 1987:there is a smallest subsemigroup 1187:, a semigroup with 0 that embeds 354:and their commutative subclass – 303:, semigroups are associated with 5508:Algebraic combinatorics on words 5184:Grillet, Pierre Antoine (2001). 5155:Grillet, Pierre Antoine (1995). 5062:Fundamentals of Semigroup Theory 4805:. Harper & Row. p. 50. 4780:. Amer. Math. Soc. p. 357. 3780:, the semigroup of relations on 3697:Theory of Groups of Finite Order 3393: 2786:as generators and all equations 1952:is a quotient of a subsemigroup 1817:if any family of congruences on 1815:maximal condition on congruences 970:form a monoid under composition. 5026:Quasigroups and Related Systems 2839:and any semigroup homomorphism 1150:denotes a monoid obtained from 266:a Cayley theorem for semigroups 5244:Hollings, Christopher (2014). 4575:Semirings with infinite sums 4444:A third generalization is the 3548: 3542: 3529: 3523: 3511: 3505: 3431: 3425: 3416: 3410: 3397: 3386: 3374: 3371: 3342: 3336: 3255: 3243: 3229: 3223: 3207: 3195: 3138: 3126: 3101: 3089: 3075: 3063: 3039: 3027: 2973:ordinary differential equation 2969:partial differential equations 317:partial differential equations 1: 5428:Topics in Operator Semigroups 5340:American Mathematical Society 5138:American Mathematical Society 4573:, in particular, Section 10, 4553:and its counterpart in which 2835:to a group: given any group 2782:generated by the elements of 2440:where every pair of elements 2116:Special classes of semigroups 2110:Special classes of semigroups 1891:is a quotient of a semigroup 1376:Homomorphisms and congruences 907:over a fixed alphabet Σ with 862:semigroup with three elements 324:special classes of semigroups 313:linear time-invariant systems 268:realizing any semigroup as a 34:Algebraic structures between 5425:Kantorovitz, Shmuel (2009). 5124:Clifford, Alfred Hoblitzelle 5088:Clifford, Alfred Hoblitzelle 4205:Commutative-and-associative 2655:Furthermore, the components 2045:. A semigroup is said to be 360:ordered algebraic structures 289:theoretical computer science 191:is not necessarily equal to 4826:Clifford & Preston 1961 4753:Clifford & Preston 2010 4501:Quantum dynamical semigroup 2823:that sends each element of 2017:generates the subsemigroup 973:The product of faces of an 855:Semigroup with two elements 816:forms a semigroup with the 278:Jordan–Hölder decomposition 209:or (less often than in the 5565: 5273:Introduction to Semigroups 4571:Semirings and Semifields 4491:Light's associativity test 2960: 2917:holds for all elements of 2901:set-theoretic intersection 2676:, there exists an element 2113: 2033:. If this is finite, then 1334:. So the subsemigroups of 1330:is also a subsemigroup of 975:arrangement of hyperplanes 860:The "flip-flop" monoid: a 824:Semigroup with one element 336:semigroups with involution 5229:10.1007/s00407-009-0044-3 5018:"On some old problems in 3797:algebraic automata theory 3724:Evgenii Sergeevich Lyapin 2580:is onto, the semilattice 2468:. The operation ∧ makes 2370:has at least one inverse 2236:Transformation semigroups 1827:ascending chain condition 1154:by adjoining an identity 941:Transformation semigroups 5476:Lawson, Mark V. (1998). 3772:composition of relations 2853:, there exists a unique 2636:, we get a homomorphism 1789:string rewriting systems 1540:belongs to the image of 1490:is also a semigroup. If 1195:Subsemigroups and ideals 1091:without identity may be 924:probability distribution 820:as the binary operation. 270:transformation semigroup 211:analogous case of groups 5271:Petrich, Mario (1973). 5128:Preston, Gordon Bamford 5092:Preston, Gordon Bamford 5032:: 15–36. Archived from 4960:Matematicheskii Sbornik 4682:Li͡apin, E. S. (1968). 3673:infinitesimal generator 2238:: any finite semigroup 2125:is a semigroup with an 1975:Structure of semigroups 1880:Quotients and divisions 1597:semigroup homomorphism 1435:holds for all elements 344:cancellative semigroups 5275:. Charles E. Merrill. 5187:Commutative Semigroups 4803:Groups, rings, modules 3812:Group-like structures 3578: 3454: 3281: 2666:Archimedean semigroups 2152:cancellative semigroup 1462:without identity into 1221:, written commonly as 903:The set of all finite 804:Examples of semigroups 213:) it may be called an 67: 5371:Mathematische Annalen 3784:. In 1997 Schein and 3756:representation theory 3747:(currently edited by 3720:James Alexander Green 3579: 3455: 3282: 2961:Further information: 2939:cancellation property 2584:is isomorphic to the 2493:Given a homomorphism 2438:partially ordered set 2343:, under the relation 2256:states. Each element 2156:cancellation property 2041:, otherwise it is of 1842:Rees factor semigroup 1357:equivalence relations 740:) that satisfies the 207:commutative semigroup 203:matrix multiplication 33: 5549:Algebraic structures 5480:. World Scientific. 5366:Suschkewitsch, Anton 5016:Dudek, W.A. (2001). 4977:B. M. Schein (1972) 3616:. As a function of 3482: 3330: 3003: 2541:, in the sense that 2456:greatest lower bound 2322:finite-state machine 2314:function composition 2143:A subsemigroup is a 1934:divides a semigroup 1620:equivalence relation 1616:semigroup congruence 1065:one-sided identities 1001:(or more generally, 952:continuous functions 887:nonnegative matrices 867:The set of positive 742:associative property 591:Group with operators 534:Complemented lattice 369:Algebraic structures 307:. In other areas of 255:preserve from groups 5299:Specific references 5190:. Springer Verlag. 5064:. Clarendon Press. 4619:, p. 30, ex. 5 4481:Generalized inverse 3813: 3801:functional analysis 3059: 2831:for morphisms from 2413:commutative algebra 2103:Krohn–Rhodes theory 2009:. A single element 1456:monoid homomorphism 966:of any object of a 645:Composition algebra 405:Quasigroup and loop 332:orthodox semigroups 322:There are numerous 309:applied mathematics 276:, analogous to the 274:Krohn–Rhodes theory 76:algebraic structure 5393:10338.dmlcz/100078 5384:10.1007/BF01459084 5330:Phillips, Ralph S. 5051:General references 4897:10.1007/BF01571659 4838:Suschkewitsch 1928 4411:, i.e. the string 4366:multiary semigroup 4362:polyadic semigroup 4251:Commutative monoid 3811: 3793:inverse semigroups 3735:Alfred H. Clifford 3675:of the semigroup. 3671:is said to be the 3574: 3569: 3450: 3277: 3272: 3045: 2947:Grothendieck group 2880:. We may think of 2855:group homomorphism 2829:universal property 2796:that hold true in 2754:group of fractions 2748:Group of fractions 2406:Inverse semigroups 2364:Regular semigroups 2335:on two generators 2329:bicyclic semigroup 2186:and similarly for 2154:is one having the 1999:, and we say that 1796:nuclear congruence 1779:. Conversely, the 1733:quotient semigroup 1685:congruence classes 1593:if there exists a 1072:two-sided identity 1041:such that for all 1009:such that for all 931:convolution powers 929:together with all 833:), the singleton { 340:inverse semigroups 328:regular semigroups 301:probability theory 166:in the semigroup. 70:In mathematics, a 68: 5517:978-0-521-18071-9 5487:978-981-02-3316-7 5468:978-0-486-47189-1 5438:978-0-8176-4932-6 5282:978-0-675-09062-9 5255:978-1-4704-1493-1 5197:978-0-7923-7067-3 5168:978-0-8247-9662-4 5161:. Marcel Dekker. 5147:978-0-8218-0272-4 5107:978-0-8218-0271-7 5071:978-0-19-851194-6 4812:978-0-06-040387-4 4787:978-0-8218-3838-9 4776:Farb, B. (2006). 4695:978-0-8218-8641-0 4660:978-3-11-015248-7 4471:Compact semigroup 4461:Absorbing element 4315: 4314: 3712:Green's relations 3708:simple semigroups 3502: 2648:. As mentioned, 2037:is said to be of 1915:is a quotient of 1353:Green's relations 1183:, one can define 1173:absorbing element 987:Identity and zero 960:identity function 956:topological space 837:} with operation 711:A semigroup is a 704: 703: 358:, which are also 282:Green's relations 215:abelian semigroup 82:together with an 16:(Redirected from 5556: 5544:Semigroup theory 5529: 5499: 5472: 5455:Jacobson, Nathan 5450: 5421: 5395: 5361: 5321: 5294: 5267: 5240: 5209: 5180: 5151: 5119: 5083: 5038: 5037: 5013: 5007: 4994: 4988: 4975: 4969: 4956: 4950: 4949: 4947: 4941:. Archived from 4940: 4932: 4923: 4922: 4915: 4909: 4908: 4877: 4871: 4870: 4868: 4867: 4858:. Archived from 4846: 4840: 4835: 4829: 4823: 4817: 4816: 4798: 4792: 4791: 4773: 4767: 4762: 4756: 4750: 4744: 4743: 4741: 4730: 4724: 4718: 4712: 4706: 4700: 4699: 4679: 4673: 4672: 4644: 4638: 4629: 4620: 4614: 4608: 4603: 4586: 4567: 4561: 4559: 4552: 4536: 4530: 4527: 4496:Principal factor 4486:Identity element 4429: 4410: 4342: 4327:binary operation 4325:equipped with a 3814: 3764:binary relations 3732: 3703:Anton Sushkevich 3667:. The operator 3662: 3641: 3607: 3583: 3581: 3580: 3575: 3573: 3572: 3563: 3562: 3504: 3503: 3495: 3459: 3457: 3456: 3451: 3446: 3445: 3406: 3405: 3396: 3370: 3369: 3354: 3353: 3315: 3304: 3286: 3284: 3283: 3278: 3276: 3275: 3222: 3221: 3058: 3053: 3023: 3022: 2995: 2988: 2916: 2879: 2869: 2852: 2822: 2795: 2781: 2758:group completion 2743: 2732: 2722: 2696: 2686: 2620: 2601: 2572: 2528: 2522: 2506: 2489: 2467: 2453: 2435: 2393: 2383: 2366:. Every element 2349: 2303: 2281: 2255: 2253: 2203: 2185: 2175: 2127:identity element 2099: 2085:maximal subgroup 2032: 1947: 1926: 1914: 1863: 1853: 1755: 1745: 1737:factor semigroup 1662: 1652: 1642: 1632: 1610: 1563: 1485: 1430: 1400: 1361:principal ideals 1355:, a set of five 1340:complete lattice 1251:it is for groups 1248: 1220: 1211:, their product 1167: 1145: 1130: 1104: 1062: 1031:. Similarly, a 1030: 1005:) is an element 850: 791: 739: 720:binary operation 718:together with a 696: 689: 682: 471:Commutative ring 400:Rack and quandle 365: 305:Markov processes 297:syntactic monoid 226:identity element 200: 190: 153: 125: 106: 88:binary operation 78:consisting of a 64:identity element 21: 18:Semigroup theory 5564: 5563: 5559: 5558: 5557: 5555: 5554: 5553: 5534: 5533: 5532: 5518: 5502: 5488: 5475: 5469: 5453: 5439: 5424: 5364: 5350: 5324: 5306:Feller, William 5304: 5301: 5283: 5270: 5256: 5243: 5212: 5198: 5183: 5169: 5154: 5148: 5136:. Vol. 2. 5122: 5108: 5086: 5072: 5056: 5053: 5047: 5042: 5041: 5015: 5014: 5010: 5000:349(1): 271–85 4995: 4991: 4976: 4972: 4957: 4953: 4945: 4938: 4934: 4933: 4926: 4917: 4916: 4912: 4879: 4878: 4874: 4865: 4863: 4848: 4847: 4843: 4836: 4832: 4824: 4820: 4813: 4800: 4799: 4795: 4788: 4775: 4774: 4770: 4763: 4759: 4751: 4747: 4739: 4732: 4731: 4727: 4719: 4715: 4707: 4703: 4696: 4681: 4680: 4676: 4661: 4646: 4645: 4641: 4630: 4623: 4615: 4611: 4604: 4600: 4595: 4590: 4589: 4568: 4564: 4554: 4547: 4537: 4533: 4528: 4524: 4519: 4476:Empty semigroup 4457: 4420: 4380: 4330: 4329:that is closed 3809: 3807:Generalizations 3779: 3749:Springer Verlag 3744:Semigroup Forum 3726: 3681: 3661: 3643: 3636: 3634: 3606: 3588: 3568: 3567: 3554: 3536: 3535: 3486: 3480: 3479: 3361: 3328: 3327: 3313: 3291: 3271: 3270: 3235: 3213: 3189: 3188: 3150: 3120: 3119: 3081: 3014: 3007: 3001: 3000: 2990: 2983: 2979:on the spatial 2965: 2959: 2951:Anatoly Maltsev 2904: 2871: 2857: 2840: 2805: 2787: 2768: 2760:of a semigroup 2750: 2738: 2724: 2723:if and only if 2705: 2688: 2681: 2663: 2603: 2602:if and only if 2593: 2571: 2558: 2550: 2542: 2518: 2516: 2508: 2494: 2477: 2459: 2441: 2429: 2422: 2394:; the elements 2385: 2375: 2374:that satisfies 2357: 2344: 2287: 2269: 2249: 2247: 2187: 2177: 2159: 2138:inverse element 2118: 2112: 2097: 2018: 1979:For any subset 1977: 1939: 1916: 1904: 1903:. For example, 1882: 1855: 1845: 1778: 1754: 1747: 1740: 1727: 1723: 1719: 1692: 1654: 1644: 1634: 1623: 1598: 1587:are said to be 1579:Two semigroups 1562: 1555: 1545: 1539: 1532: 1525: 1514: 1503: 1496: 1484: 1477: 1467: 1405: 1388: 1378: 1317:two-sided ideal 1299:is a subset of 1284:is a subset of 1269:is a subset of 1226: 1212: 1207:of a semigroup 1197: 1168:for a monoid). 1159: 1146:. The notation 1132: 1110: 1096: 1050: 1018: 997:of a semigroup 989: 984: 838: 810:Empty semigroup 806: 765: 764:, the equation 726: 709: 700: 671: 670: 669: 640:Non-associative 622: 611: 610: 600: 580: 569: 568: 557:Map of lattices 553: 549:Boolean algebra 544:Heyting algebra 518: 507: 506: 500: 481:Integral domain 445: 434: 433: 427: 381: 293:finite automata 192: 182: 127: 115: 98: 28: 23: 22: 15: 12: 11: 5: 5562: 5560: 5552: 5551: 5546: 5536: 5535: 5531: 5530: 5516: 5500: 5486: 5473: 5467: 5451: 5437: 5422: 5362: 5349:978-0821874646 5348: 5322: 5300: 5297: 5296: 5295: 5281: 5268: 5254: 5241: 5223:(5): 497–536. 5210: 5196: 5181: 5167: 5152: 5146: 5120: 5106: 5084: 5070: 5058:Howie, John M. 5052: 5049: 5048: 5046: 5043: 5040: 5039: 5036:on 2009-07-14. 5008: 4989: 4970: 4951: 4948:on 2009-10-25. 4924: 4910: 4872: 4850:Preston, G. B. 4841: 4830: 4818: 4811: 4793: 4786: 4768: 4757: 4745: 4725: 4713: 4701: 4694: 4674: 4659: 4639: 4621: 4609: 4597: 4596: 4594: 4591: 4588: 4587: 4562: 4531: 4521: 4520: 4518: 4515: 4514: 4513: 4508: 4506:Semigroup ring 4503: 4498: 4493: 4488: 4483: 4478: 4473: 4468: 4463: 4456: 4453: 4377:-ary operation 4351:-ary semigroup 4313: 4312: 4309: 4306: 4303: 4300: 4297: 4291: 4290: 4287: 4284: 4281: 4278: 4275: 4269: 4268: 4265: 4262: 4259: 4256: 4253: 4247: 4246: 4243: 4240: 4237: 4234: 4231: 4225: 4224: 4221: 4218: 4215: 4212: 4209: 4202: 4201: 4198: 4195: 4192: 4189: 4186: 4179: 4178: 4175: 4172: 4169: 4166: 4163: 4156: 4155: 4152: 4149: 4146: 4143: 4140: 4134: 4133: 4130: 4127: 4124: 4121: 4118: 4111: 4110: 4107: 4104: 4101: 4098: 4095: 4089: 4088: 4085: 4082: 4079: 4076: 4073: 4066: 4065: 4062: 4059: 4056: 4053: 4050: 4044: 4043: 4040: 4037: 4034: 4031: 4028: 4021: 4020: 4017: 4014: 4011: 4008: 4005: 3999: 3998: 3995: 3992: 3989: 3986: 3983: 3976: 3975: 3972: 3969: 3966: 3963: 3960: 3954: 3953: 3950: 3947: 3944: 3941: 3938: 3931: 3930: 3927: 3924: 3921: 3918: 3915: 3909: 3908: 3905: 3902: 3899: 3896: 3893: 3891:Small category 3887: 3886: 3883: 3880: 3877: 3874: 3871: 3865: 3864: 3861: 3858: 3855: 3852: 3849: 3843: 3842: 3837: 3832: 3827: 3822: 3817: 3808: 3805: 3786:Ralph McKenzie 3775: 3739:Gordon Preston 3680: 3677: 3659: 3632: 3604: 3585: 3584: 3571: 3566: 3561: 3557: 3553: 3550: 3547: 3544: 3541: 3538: 3537: 3534: 3531: 3528: 3525: 3522: 3519: 3516: 3513: 3510: 3507: 3501: 3498: 3492: 3491: 3489: 3461: 3460: 3449: 3444: 3439: 3436: 3433: 3430: 3427: 3424: 3421: 3418: 3415: 3412: 3409: 3404: 3399: 3395: 3391: 3388: 3385: 3382: 3379: 3376: 3373: 3368: 3364: 3360: 3357: 3352: 3347: 3344: 3341: 3338: 3335: 3288: 3287: 3274: 3269: 3266: 3263: 3260: 3257: 3254: 3251: 3248: 3245: 3242: 3239: 3236: 3234: 3231: 3228: 3225: 3220: 3216: 3212: 3209: 3206: 3203: 3200: 3197: 3194: 3191: 3190: 3187: 3184: 3181: 3178: 3175: 3172: 3169: 3166: 3163: 3160: 3157: 3154: 3151: 3149: 3146: 3143: 3140: 3137: 3134: 3131: 3128: 3125: 3122: 3121: 3118: 3115: 3112: 3109: 3106: 3103: 3100: 3097: 3094: 3091: 3088: 3085: 3082: 3080: 3077: 3074: 3071: 3068: 3065: 3062: 3057: 3052: 3048: 3044: 3041: 3038: 3035: 3032: 3029: 3026: 3021: 3017: 3013: 3012: 3010: 2958: 2955: 2749: 2746: 2659: 2563: 2554: 2546: 2512: 2421: 2418: 2417: 2416: 2409: 2403: 2361: 2355: 2351: 2333:free semigroup 2325: 2286:is defined by 2233: 2227: 2216: 2205: 2148: 2141: 2130: 2114:Main article: 2111: 2108: 2043:infinite order 1995:that contains 1976: 1973: 1881: 1878: 1813:satisfies the 1776: 1752: 1746:. The mapping 1739:, and denoted 1729: 1728: 1725: 1721: 1717: 1711: 1710: 1690: 1560: 1553: 1537: 1530: 1523: 1512: 1501: 1494: 1482: 1475: 1433: 1432: 1377: 1374: 1305: 1304: 1289: 1274: 1196: 1193: 1037:is an element 1034:right identity 988: 985: 983: 982:Basic concepts 980: 979: 978: 971: 948: 938: 920: 913:free semigroup 901: 890: 883: 876: 865: 858: 852: 821: 818:empty function 805: 802: 794: 793: 722:⋅ (that is, a 708: 705: 702: 701: 699: 698: 691: 684: 676: 673: 672: 668: 667: 662: 657: 652: 647: 642: 637: 631: 630: 629: 623: 617: 616: 613: 612: 609: 608: 605:Linear algebra 599: 598: 593: 588: 582: 581: 575: 574: 571: 570: 567: 566: 563:Lattice theory 559: 552: 551: 546: 541: 536: 531: 526: 520: 519: 513: 512: 509: 508: 499: 498: 493: 488: 483: 478: 473: 468: 463: 458: 453: 447: 446: 440: 439: 436: 435: 426: 425: 420: 415: 409: 408: 407: 402: 397: 388: 382: 376: 375: 372: 371: 257:the notion of 95:multiplication 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 5561: 5550: 5547: 5545: 5542: 5541: 5539: 5527: 5523: 5519: 5513: 5509: 5505: 5501: 5497: 5493: 5489: 5483: 5479: 5474: 5470: 5464: 5460: 5459:Basic algebra 5456: 5452: 5448: 5444: 5440: 5434: 5430: 5429: 5423: 5419: 5415: 5411: 5407: 5403: 5399: 5394: 5389: 5385: 5381: 5377: 5373: 5372: 5367: 5363: 5359: 5355: 5351: 5345: 5341: 5337: 5336: 5331: 5327: 5323: 5319: 5315: 5311: 5307: 5303: 5302: 5298: 5292: 5288: 5284: 5278: 5274: 5269: 5265: 5261: 5257: 5251: 5247: 5242: 5238: 5234: 5230: 5226: 5222: 5218: 5217: 5211: 5207: 5203: 5199: 5193: 5189: 5188: 5182: 5178: 5174: 5170: 5164: 5160: 5159: 5153: 5149: 5143: 5139: 5135: 5134: 5129: 5125: 5121: 5117: 5113: 5109: 5103: 5099: 5098: 5093: 5089: 5085: 5081: 5077: 5073: 5067: 5063: 5059: 5055: 5054: 5050: 5044: 5035: 5031: 5027: 5023: 5021: 5012: 5009: 5006: 5003: 4999: 4993: 4990: 4987: 4984: 4980: 4974: 4971: 4968: 4965: 4961: 4955: 4952: 4944: 4937: 4931: 4929: 4925: 4920: 4914: 4911: 4906: 4902: 4898: 4894: 4890: 4886: 4885:Math. Annalen 4882: 4876: 4873: 4862:on 2009-01-09 4861: 4857: 4856: 4851: 4845: 4842: 4839: 4834: 4831: 4827: 4822: 4819: 4814: 4808: 4804: 4797: 4794: 4789: 4783: 4779: 4772: 4769: 4766: 4761: 4758: 4754: 4749: 4746: 4742:. p. 19. 4738: 4737: 4729: 4726: 4723:, p. 465 4722: 4721:Lothaire 2011 4717: 4714: 4711:, p. 463 4710: 4709:Lothaire 2011 4705: 4702: 4697: 4691: 4687: 4686: 4678: 4675: 4670: 4666: 4662: 4656: 4652: 4651: 4643: 4640: 4637: 4633: 4628: 4626: 4622: 4618: 4617:Jacobson 2009 4613: 4610: 4607: 4602: 4599: 4592: 4584: 4580: 4576: 4572: 4566: 4563: 4557: 4550: 4545: 4541: 4535: 4532: 4526: 4523: 4516: 4512: 4509: 4507: 4504: 4502: 4499: 4497: 4494: 4492: 4489: 4487: 4484: 4482: 4479: 4477: 4474: 4472: 4469: 4467: 4466:Biordered set 4464: 4462: 4459: 4458: 4454: 4452: 4449: 4447: 4442: 4440: 4438: 4433: 4427: 4423: 4418: 4414: 4408: 4404: 4400: 4396: 4392: 4388: 4384: 4378: 4376: 4371: 4367: 4363: 4359: 4357: 4352: 4350: 4344: 4341: 4337: 4333: 4328: 4324: 4320: 4310: 4307: 4304: 4301: 4298: 4296: 4295:Abelian group 4293: 4292: 4288: 4285: 4282: 4279: 4276: 4274: 4271: 4270: 4266: 4263: 4260: 4257: 4254: 4252: 4249: 4248: 4244: 4241: 4238: 4235: 4232: 4230: 4227: 4226: 4222: 4219: 4216: 4213: 4210: 4208: 4204: 4203: 4199: 4196: 4193: 4190: 4187: 4185: 4181: 4180: 4176: 4173: 4170: 4167: 4164: 4162: 4158: 4157: 4153: 4150: 4147: 4144: 4141: 4139: 4136: 4135: 4131: 4128: 4125: 4122: 4119: 4117: 4113: 4112: 4108: 4105: 4102: 4099: 4096: 4094: 4091: 4090: 4086: 4083: 4080: 4077: 4074: 4072: 4068: 4067: 4063: 4060: 4057: 4054: 4051: 4049: 4046: 4045: 4041: 4038: 4035: 4032: 4029: 4027: 4023: 4022: 4018: 4015: 4012: 4009: 4006: 4004: 4001: 4000: 3996: 3993: 3990: 3987: 3984: 3982: 3978: 3977: 3973: 3970: 3967: 3964: 3961: 3959: 3956: 3955: 3951: 3948: 3945: 3942: 3939: 3937: 3933: 3932: 3928: 3925: 3922: 3919: 3916: 3914: 3911: 3910: 3906: 3903: 3900: 3897: 3894: 3892: 3889: 3888: 3884: 3881: 3878: 3875: 3872: 3870: 3867: 3866: 3862: 3859: 3856: 3853: 3850: 3848: 3847:Partial magma 3845: 3844: 3841: 3838: 3836: 3833: 3831: 3828: 3826: 3823: 3821: 3818: 3816: 3815: 3806: 3804: 3802: 3798: 3794: 3789: 3787: 3783: 3778: 3773: 3769: 3765: 3761: 3757: 3752: 3750: 3746: 3745: 3740: 3736: 3730: 3725: 3721: 3717: 3713: 3709: 3704: 3700: 3698: 3694: 3690: 3686: 3678: 3676: 3674: 3670: 3666: 3658: 3654: 3650: 3646: 3642:to the state 3639: 3631: 3627: 3623: 3619: 3615: 3611: 3603: 3599: 3595: 3591: 3564: 3559: 3555: 3551: 3545: 3539: 3532: 3526: 3520: 3517: 3514: 3508: 3499: 3496: 3487: 3478: 3477: 3476: 3474: 3470: 3469:Sobolev space 3466: 3447: 3437: 3434: 3428: 3422: 3419: 3413: 3407: 3389: 3383: 3380: 3377: 3366: 3362: 3358: 3355: 3345: 3339: 3333: 3326: 3325: 3324: 3323: 3319: 3311: 3309: 3302: 3298: 3294: 3267: 3264: 3261: 3258: 3252: 3249: 3246: 3240: 3237: 3232: 3226: 3218: 3214: 3210: 3204: 3201: 3198: 3192: 3185: 3182: 3179: 3176: 3173: 3167: 3164: 3161: 3155: 3152: 3147: 3144: 3141: 3135: 3132: 3129: 3123: 3116: 3113: 3110: 3107: 3104: 3098: 3095: 3092: 3086: 3083: 3078: 3072: 3069: 3066: 3060: 3055: 3050: 3042: 3036: 3033: 3030: 3024: 3019: 3008: 2999: 2998: 2997: 2993: 2987: 2982: 2978: 2977:heat equation 2974: 2970: 2964: 2956: 2954: 2952: 2948: 2944: 2940: 2936: 2932: 2931:trivial group 2928: 2924: 2920: 2915: 2911: 2907: 2902: 2898: 2894: 2889: 2887: 2883: 2878: 2874: 2868: 2864: 2860: 2856: 2851: 2847: 2843: 2838: 2834: 2830: 2826: 2820: 2816: 2812: 2808: 2803: 2799: 2794: 2790: 2785: 2779: 2775: 2771: 2767: 2763: 2759: 2755: 2747: 2745: 2741: 2736: 2731: 2727: 2720: 2716: 2712: 2708: 2703: 2698: 2695: 2691: 2684: 2679: 2675: 2671: 2667: 2662: 2658: 2653: 2651: 2647: 2643: 2639: 2635: 2631: 2627: 2622: 2618: 2614: 2610: 2606: 2600: 2596: 2591: 2587: 2583: 2579: 2574: 2570: 2566: 2562: 2557: 2553: 2549: 2545: 2540: 2536: 2532: 2526: 2521: 2515: 2511: 2505: 2501: 2497: 2491: 2488: 2484: 2480: 2475: 2471: 2466: 2462: 2457: 2452: 2448: 2444: 2439: 2433: 2427: 2419: 2414: 2410: 2407: 2404: 2401: 2397: 2392: 2388: 2382: 2378: 2373: 2369: 2365: 2362: 2359: 2352: 2347: 2342: 2338: 2334: 2330: 2326: 2323: 2319: 2315: 2311: 2307: 2302: 2298: 2294: 2290: 2285: 2282:and sequence 2280: 2276: 2272: 2267: 2263: 2259: 2252: 2245: 2241: 2237: 2234: 2231: 2228: 2225: 2221: 2217: 2214: 2210: 2206: 2202: 2198: 2194: 2190: 2184: 2180: 2174: 2170: 2166: 2162: 2157: 2153: 2149: 2146: 2142: 2139: 2135: 2131: 2128: 2124: 2120: 2119: 2117: 2109: 2107: 2105: 2104: 2094: 2089: 2087: 2086: 2081: 2077: 2073: 2072: 2066: 2064: 2060: 2056: 2052: 2048: 2044: 2040: 2036: 2030: 2026: 2022: 2016: 2012: 2008: 2005: 2002: 1998: 1994: 1990: 1986: 1982: 1974: 1972: 1969: 1967: 1963: 1959: 1955: 1951: 1946: 1942: 1937: 1933: 1928: 1924: 1920: 1912: 1908: 1902: 1898: 1894: 1890: 1885: 1879: 1877: 1875: 1871: 1867: 1862: 1858: 1852: 1848: 1843: 1839: 1834: 1832: 1828: 1824: 1820: 1816: 1812: 1807: 1805: 1801: 1797: 1792: 1790: 1786: 1782: 1774: 1770: 1766: 1765: 1759: 1750: 1743: 1738: 1734: 1716: 1715: 1714: 1708: 1704: 1700: 1696: 1689: 1688: 1687: 1686: 1682: 1678: 1674: 1670: 1666: 1661: 1657: 1651: 1647: 1641: 1637: 1631: 1627: 1621: 1617: 1612: 1609: 1605: 1601: 1596: 1592: 1591: 1586: 1582: 1577: 1575: 1571: 1567: 1559: 1552: 1548: 1543: 1536: 1529: 1522: 1518: 1511: 1507: 1500: 1493: 1489: 1481: 1474: 1470: 1465: 1461: 1457: 1452: 1450: 1446: 1442: 1438: 1428: 1424: 1420: 1416: 1412: 1408: 1404: 1403: 1402: 1399: 1395: 1391: 1386: 1385: 1375: 1373: 1371: 1370: 1364: 1362: 1358: 1354: 1350: 1348: 1343: 1341: 1337: 1333: 1329: 1325: 1320: 1318: 1314: 1310: 1302: 1298: 1294: 1290: 1287: 1283: 1279: 1275: 1272: 1268: 1264: 1260: 1259: 1258: 1256: 1252: 1246: 1242: 1238: 1234: 1230: 1225:, is the set 1224: 1219: 1215: 1210: 1206: 1202: 1194: 1192: 1190: 1186: 1182: 1178: 1174: 1169: 1166: 1162: 1157: 1153: 1149: 1143: 1139: 1135: 1129: 1125: 1121: 1117: 1113: 1109:and defining 1108: 1103: 1099: 1094: 1090: 1085: 1083: 1082: 1077: 1073: 1068: 1066: 1061: 1057: 1053: 1048: 1044: 1040: 1036: 1035: 1029: 1025: 1021: 1016: 1012: 1008: 1004: 1000: 996: 995: 994:left identity 986: 981: 976: 972: 969: 965: 964:endomorphisms 961: 957: 953: 949: 946: 942: 939: 936: 932: 928: 925: 921: 918: 914: 910: 909:concatenation 906: 902: 899: 895: 891: 888: 884: 881: 877: 874: 870: 866: 863: 859: 856: 853: 849: 845: 841: 836: 832: 829: 825: 822: 819: 815: 811: 808: 807: 803: 801: 799: 789: 785: 781: 777: 773: 769: 763: 759: 755: 751: 747: 746: 745: 743: 738: 734: 730: 725: 721: 717: 714: 706: 697: 692: 690: 685: 683: 678: 677: 675: 674: 666: 663: 661: 658: 656: 653: 651: 648: 646: 643: 641: 638: 636: 633: 632: 628: 625: 624: 620: 615: 614: 607: 606: 602: 601: 597: 594: 592: 589: 587: 584: 583: 578: 573: 572: 565: 564: 560: 558: 555: 554: 550: 547: 545: 542: 540: 537: 535: 532: 530: 527: 525: 522: 521: 516: 511: 510: 505: 504: 497: 494: 492: 491:Division ring 489: 487: 484: 482: 479: 477: 474: 472: 469: 467: 464: 462: 459: 457: 454: 452: 449: 448: 443: 438: 437: 432: 431: 424: 421: 419: 416: 414: 413:Abelian group 411: 410: 406: 403: 401: 398: 396: 392: 389: 387: 384: 383: 379: 374: 373: 370: 366: 363: 361: 357: 353: 349: 348:trivial group 345: 341: 337: 333: 329: 325: 320: 318: 314: 310: 306: 302: 298: 294: 290: 285: 283: 279: 275: 271: 267: 262: 260: 256: 252: 247: 243: 239: 235: 234:concatenation 231: 227: 223: 218: 216: 212: 208: 204: 199: 195: 189: 185: 180: 176: 172: 167: 165: 161: 157: 151: 147: 143: 139: 135: 131: 123: 119: 114: 110: 105: 101: 96: 91: 89: 85: 81: 77: 73: 65: 61: 57: 53: 52:associativity 49: 45: 41: 37: 32: 19: 5507: 5504:Lothaire, M. 5477: 5458: 5431:. Springer. 5427: 5378:(1): 30–50. 5375: 5369: 5334: 5326:Hille, Einar 5309: 5272: 5245: 5220: 5214: 5186: 5157: 5132: 5096: 5061: 5034:the original 5029: 5025: 5022:-ary groups" 5019: 5011: 4992: 4978: 4973: 4962:60: 292–303 4954: 4943:the original 4913: 4888: 4884: 4875: 4864:. Retrieved 4860:the original 4854: 4844: 4833: 4828:, p. 34 4821: 4802: 4796: 4777: 4771: 4765:Grillet 2001 4760: 4748: 4735: 4728: 4716: 4704: 4684: 4677: 4649: 4642: 4612: 4601: 4582: 4581:in place of 4578: 4574: 4570: 4565: 4555: 4548: 4543: 4539: 4534: 4525: 4511:Weak inverse 4450: 4446:semigroupoid 4443: 4436: 4431: 4425: 4421: 4416: 4412: 4406: 4402: 4398: 4394: 4390: 4386: 4382: 4374: 4369: 4365: 4361: 4355: 4354: 4348: 4347: 4345: 4339: 4335: 4331: 4322: 4316: 4182:Associative 4160: 4159:Commutative 4137: 4114:Commutative 4071:unital magma 4069:Commutative 4048:Unital magma 4024:Commutative 3979:Commutative 3934:Commutative 3869:Semigroupoid 3835:Cancellation 3790: 3781: 3776: 3767: 3760:Boris Schein 3753: 3742: 3701: 3696: 3692: 3682: 3668: 3664: 3656: 3652: 3648: 3644: 3637: 3629: 3625: 3621: 3617: 3613: 3601: 3597: 3593: 3589: 3586: 3472: 3464: 3462: 3317: 3307: 3300: 3296: 3292: 3289: 2991: 2985: 2966: 2963:C0-semigroup 2942: 2934: 2926: 2922: 2918: 2913: 2909: 2905: 2896: 2892: 2890: 2885: 2881: 2876: 2872: 2866: 2862: 2858: 2849: 2845: 2841: 2836: 2832: 2824: 2818: 2814: 2810: 2806: 2797: 2792: 2788: 2783: 2777: 2773: 2769: 2761: 2757: 2753: 2751: 2739: 2734: 2729: 2725: 2718: 2714: 2710: 2706: 2701: 2699: 2693: 2689: 2682: 2677: 2673: 2669: 2660: 2656: 2654: 2649: 2645: 2641: 2637: 2633: 2629: 2625: 2623: 2616: 2612: 2608: 2604: 2598: 2594: 2589: 2581: 2577: 2575: 2568: 2564: 2560: 2555: 2551: 2547: 2543: 2538: 2534: 2530: 2524: 2519: 2513: 2509: 2503: 2499: 2495: 2492: 2486: 2482: 2478: 2469: 2464: 2460: 2450: 2446: 2442: 2431: 2426:semilattices 2423: 2399: 2395: 2390: 2386: 2380: 2376: 2371: 2367: 2345: 2340: 2336: 2309: 2305: 2300: 2296: 2292: 2288: 2283: 2278: 2274: 2270: 2268:into itself 2265: 2261: 2257: 2250: 2243: 2239: 2200: 2196: 2192: 2188: 2182: 2178: 2172: 2168: 2164: 2160: 2101: 2090: 2083: 2079: 2075: 2069: 2067: 2046: 2042: 2039:finite order 2038: 2034: 2028: 2024: 2020: 2014: 2010: 2006: 2003: 2000: 1996: 1992: 1988: 1984: 1980: 1978: 1970: 1965: 1961: 1957: 1953: 1949: 1944: 1940: 1935: 1931: 1930:A semigroup 1929: 1922: 1918: 1910: 1906: 1900: 1896: 1892: 1888: 1887:A semigroup 1886: 1883: 1873: 1869: 1865: 1860: 1856: 1850: 1846: 1837: 1836:Every ideal 1835: 1830: 1823:Zorn's lemma 1818: 1814: 1810: 1809:A semigroup 1808: 1803: 1799: 1795: 1793: 1772: 1768: 1761: 1758:quotient map 1757: 1748: 1741: 1736: 1732: 1730: 1712: 1706: 1702: 1698: 1694: 1680: 1676: 1672: 1668: 1664: 1659: 1655: 1649: 1645: 1639: 1635: 1629: 1625: 1615: 1613: 1607: 1603: 1599: 1588: 1584: 1580: 1578: 1569: 1565: 1557: 1550: 1546: 1541: 1534: 1527: 1520: 1516: 1509: 1505: 1498: 1491: 1487: 1479: 1472: 1468: 1463: 1459: 1453: 1448: 1444: 1440: 1436: 1434: 1426: 1422: 1418: 1414: 1410: 1406: 1397: 1393: 1389: 1384:homomorphism 1381: 1379: 1367: 1365: 1351: 1344: 1335: 1331: 1327: 1323: 1321: 1316: 1312: 1308: 1306: 1300: 1296: 1292: 1285: 1281: 1277: 1270: 1266: 1263:subsemigroup 1262: 1254: 1244: 1240: 1236: 1232: 1228: 1222: 1217: 1213: 1208: 1204: 1200: 1198: 1188: 1184: 1180: 1176: 1170: 1164: 1160: 1156:if necessary 1155: 1151: 1147: 1141: 1137: 1133: 1127: 1123: 1119: 1115: 1111: 1106: 1101: 1097: 1088: 1087:A semigroup 1086: 1079: 1075: 1071: 1069: 1064: 1059: 1055: 1051: 1046: 1042: 1038: 1032: 1027: 1023: 1019: 1014: 1010: 1006: 998: 992: 990: 934: 926: 847: 843: 839: 834: 795: 787: 783: 779: 775: 771: 767: 761: 757: 753: 749: 736: 732: 728: 715: 710: 665:Hopf algebra 603: 596:Vector space 561: 501: 430:Group theory 428: 393: / 390: 356:semilattices 321: 286: 263: 219: 214: 206: 197: 193: 187: 183: 168: 163: 159: 155: 149: 145: 141: 137: 133: 129: 121: 117: 113:ordered pair 108: 107:, or simply 103: 99: 92: 71: 69: 59: 43: 4891:: 686–691. 4881:Maltsev, A. 4755:, p. 3 4632:Lawson 1998 4606:Feller 1971 3840:Commutative 3825:Associative 3727: [ 3610:exponential 2474:idempotence 2358:-semigroups 2246:of at most 2232:semigroups. 2224:commutative 2220:semilattice 1347:commutative 1278:right ideal 950:The set of 917:free monoid 878:The set of 831:isomorphism 650:Lie algebra 635:Associative 539:Total order 529:Semilattice 503:Ring theory 251:quasigroups 179:commutative 84:associative 5538:Categories 5526:1221.68183 5496:1079.20505 5447:1187.47003 5291:0321.20037 5264:1317.20001 5206:1040.20048 5177:0830.20079 5116:0111.03403 5080:0835.20077 5045:References 4866:2009-05-12 4685:Semigroups 4669:0945.20036 4634:, p.  4579:semimodule 4439:-ary group 4358:-semigroup 4207:quasigroup 4184:quasigroup 4026:quasigroup 4003:Quasigroup 3716:David Rees 2989:and times 2687:such that 2458:, denoted 2264:then maps 2254:| + 1 2213:idempotent 2063:idempotent 1938:, denoted 1864:, or both 1854:if either 1769:projection 1764:surjection 1762:canonical 1663:for every 1590:isomorphic 1574:surjective 1382:semigroup 1293:left ideal 1257:is called 707:Definition 5506:(2011) . 5418:121081075 5402:0025-5831 5237:123422715 5130:(2010) . 4905:122295935 4593:Citations 4583:semigroup 4430:with any 4311:Required 4289:Unneeded 4267:Required 4245:Unneeded 4223:Required 4200:Unneeded 4177:Required 4161:semigroup 4154:Unneeded 4138:Semigroup 4132:Required 4109:Unneeded 4087:Required 4064:Unneeded 4042:Required 4019:Unneeded 3997:Required 3974:Unneeded 3952:Required 3929:Unneeded 3907:Unneeded 3885:Unneeded 3863:Unneeded 3766:on a set 3500:˙ 3359:∈ 3241:∈ 3156:∈ 3087:∈ 3047:∂ 3016:∂ 2984:(0, 1) ⊂ 2937:have the 2802:relations 2733:for some 2318:automaton 2304:for each 2051:monogenic 2004:generates 1595:bijective 1074:(or just 814:empty set 727:⋅ : 660:Bialgebra 466:Near-ring 423:Lie group 391:Semigroup 86:internal 72:semigroup 60:semigroup 44:semigroup 5457:(2009). 5332:(1974). 5308:(1971). 5094:(1961). 5060:(1995). 4852:(1990). 4455:See also 4308:Required 4305:Required 4302:Required 4299:Required 4286:Required 4283:Required 4280:Required 4277:Required 4264:Unneeded 4261:Required 4258:Required 4255:Required 4242:Unneeded 4239:Required 4236:Required 4233:Required 4220:Required 4217:Unneeded 4214:Required 4211:Required 4197:Required 4194:Unneeded 4191:Required 4188:Required 4174:Unneeded 4171:Unneeded 4168:Required 4165:Required 4151:Unneeded 4148:Unneeded 4145:Required 4142:Required 4129:Required 4126:Required 4123:Unneeded 4120:Required 4106:Required 4103:Required 4100:Unneeded 4097:Required 4084:Unneeded 4081:Required 4078:Unneeded 4075:Required 4061:Unneeded 4058:Required 4055:Unneeded 4052:Required 4039:Required 4036:Unneeded 4033:Unneeded 4030:Required 4016:Required 4013:Unneeded 4010:Unneeded 4007:Required 3994:Unneeded 3991:Unneeded 3988:Unneeded 3985:Required 3971:Unneeded 3968:Unneeded 3965:Unneeded 3962:Required 3949:Required 3946:Required 3943:Required 3940:Unneeded 3936:Groupoid 3926:Required 3923:Required 3920:Required 3917:Unneeded 3913:Groupoid 3904:Unneeded 3901:Required 3898:Required 3895:Unneeded 3882:Unneeded 3879:Unneeded 3876:Required 3873:Unneeded 3860:Unneeded 3857:Unneeded 3854:Unneeded 3851:Unneeded 3830:Identity 3663:at time 3651:) = exp( 3635:at time 3596:) = exp( 3316:and let 3299:((0, 1) 2981:interval 2941:. When 2861: : 2844: : 2809: : 2664:are all 2586:quotient 2533:becomes 2498: : 2273: : 2230:0-simple 2176:implies 2071:subgroup 2059:integers 2047:periodic 1960:divides 1653:implies 1618:~ is an 1602: : 1471: : 1392: : 1131:for all 1093:embedded 1076:identity 968:category 880:integers 869:integers 748:For all 724:function 496:Lie ring 461:Semiring 295:via the 259:division 246:integers 242:integers 154:for all 62:with an 5410:1512437 5358:0423094 5318:0270403 5005:1370647 4986:0401970 4967:0153760 4372:with a 3820:Closure 3679:History 3305:be the 2764:is the 1872:are in 1701:| 1564:, i.e. 1544:, then 1504:, then 1338:form a 1081:monoids 954:from a 945:monoids 919:over Σ. 905:strings 885:Square 627:Algebra 619:Algebra 524:Lattice 515:Lattice 238:strings 230:strings 90:on it. 5524:  5514:  5494:  5484:  5465:  5445:  5435:  5416:  5408:  5400:  5356:  5346:  5316:  5289:  5279:  5262:  5252:  5235:  5204:  5194:  5175:  5165:  5144:  5114:  5104:  5078:  5068:  4903:  4809:  4784:  4692:  4667:  4657:  4353:(also 4229:Monoid 3762:using 3685:groups 3620:, exp( 3463:where 3322:domain 3314:(0, 1) 2742:> 0 2685:> 0 2535:graded 2454:has a 2324:(FSM). 2248:| 2145:subset 2123:monoid 2055:cyclic 1781:kernel 1369:center 1315:(or a 873:monoid 812:: the 792:holds. 655:Graded 586:Module 577:Module 476:Domain 395:Monoid 315:. In 299:. In 222:monoid 175:groups 171:magmas 74:is an 56:monoid 40:groups 36:magmas 5414:S2CID 5233:S2CID 4946:(PDF) 4939:(PDF) 4901:S2CID 4740:(PDF) 4517:Notes 4413:abcde 4319:magma 4273:Group 3981:magma 3958:Magma 3731:] 3689:rings 3467:is a 3310:space 2899:with 2870:with 2766:group 2644:onto 2640:from 2436:is a 2295:) = ( 2134:group 2098:{a, b 2093:ideal 1771:; if 1519:. If 1313:ideal 1288:, and 1003:magma 896:of a 894:ideal 828:up to 798:magma 621:-like 579:-like 517:-like 486:Field 444:-like 418:Magma 386:Group 380:-like 378:Group 352:bands 232:with 181:, so 58:is a 50:with 48:magma 46:is a 5512:ISBN 5482:ISBN 5463:ISBN 5433:ISBN 5398:ISSN 5344:ISBN 5277:ISBN 5250:ISBN 5192:ISBN 5163:ISBN 5142:ISBN 5102:ISBN 5066:ISBN 4807:ISBN 4782:ISBN 4690:ISBN 4655:ISBN 4542:and 4428:− 1) 4116:loop 4093:Loop 3770:and 3754:The 3737:and 3290:Let 3180:> 3111:> 2752:The 2737:and 2713:) ≤ 2680:and 2611:) = 2476:law 2434:, ≤) 2398:and 2384:and 2339:and 2327:The 2209:band 2053:(or 1925:, +) 1913:, +) 1868:and 1643:and 1624:~ ⊆ 1583:and 1556:) = 1533:and 1413:) = 1239:and 1203:and 1177:zero 943:and 898:ring 892:Any 774:) ⋅ 451:Ring 442:Ring 342:and 162:and 136:) ⋅ 54:. A 42:: A 38:and 5522:Zbl 5492:Zbl 5443:Zbl 5388:hdl 5380:doi 5287:Zbl 5260:Zbl 5225:doi 5202:Zbl 5173:Zbl 5112:Zbl 5076:Zbl 4893:doi 4889:113 4665:Zbl 4558:= b 4551:= a 4424:+ ( 4407:cde 4395:bcd 4383:abc 4364:or 3687:or 3640:= 0 3612:of 2994:≥ 0 2800:as 2756:or 2588:of 2576:If 2537:by 2387:yxy 2377:xyx 2348:= 1 2320:or 2308:in 2260:of 2013:of 1991:of 1983:of 1948:if 1899:to 1798:on 1767:or 1744:/ ~ 1735:or 1693:= { 1679:in 1572:is 1443:in 1322:If 1319:). 1307:If 1295:if 1280:if 1265:if 1243:in 1235:in 1140:∪ { 1105:to 1045:in 1013:in 933:of 782:⋅ ( 713:set 456:Rng 144:⋅ ( 97:): 80:set 5540:: 5520:. 5490:. 5441:. 5412:. 5406:MR 5404:. 5396:. 5386:. 5376:99 5374:. 5354:MR 5352:. 5342:. 5338:. 5328:; 5314:MR 5285:. 5258:. 5231:. 5221:63 5219:. 5200:. 5171:. 5140:. 5126:; 5110:. 5090:; 5074:. 5028:. 5024:. 5002:MR 4983:MR 4981:, 4964:MR 4927:^ 4899:. 4887:. 4663:. 4636:20 4624:^ 4556:xy 4549:xy 4546:) 4441:. 4403:ab 4401:= 4389:= 4387:de 4360:, 4343:. 4338:→ 4334:× 3803:. 3733:, 3729:fr 3722:, 3718:, 3699:. 3653:tA 3622:tA 3614:tA 3598:tA 3475:: 3295:= 3268:0. 2996:: 2912:= 2888:. 2877:fj 2875:= 2865:→ 2848:→ 2813:→ 2791:= 2789:xy 2772:= 2744:. 2730:yz 2728:= 2697:. 2694:yz 2692:= 2674:y 2672:, 2597:~ 2573:. 2559:⊆ 2517:= 2502:→ 2490:. 2485:= 2481:∧ 2463:∧ 2449:∈ 2445:, 2389:= 2379:= 2346:pq 2297:qx 2293:xy 2284:xy 2277:→ 2218:A 2207:A 2199:· 2195:= 2191:· 2181:= 2171:· 2167:= 2163:· 2158:: 2150:A 2132:A 2121:A 2106:. 2027:∈ 2023:| 2019:{ 1968:. 1943:≼ 1921:/4 1909:/2 1876:. 1859:= 1849:ρ 1833:. 1806:. 1794:A 1791:. 1760:, 1751:↦ 1724:= 1720:∘ 1705:~ 1697:∈ 1675:, 1671:, 1667:, 1660:yv 1658:~ 1656:xu 1648:~ 1638:~ 1628:× 1614:A 1606:→ 1478:→ 1451:. 1439:, 1411:ab 1396:→ 1380:A 1342:. 1297:SA 1291:a 1282:AS 1276:a 1267:AA 1261:a 1247:}. 1231:| 1229:ab 1227:{ 1223:AB 1216:· 1191:. 1163:= 1136:∈ 1126:= 1122:⋅ 1118:= 1114:⋅ 1100:∉ 1070:A 1058:= 1054:⋅ 1049:, 1026:= 1022:⋅ 1017:, 991:A 922:A 875:.) 846:= 842:· 800:. 786:⋅ 778:= 770:⋅ 760:∈ 756:, 752:, 744:: 735:→ 731:× 362:. 338:, 334:, 330:, 220:A 217:. 196:⋅ 186:⋅ 158:, 148:⋅ 140:= 132:⋅ 120:, 109:xy 102:⋅ 5528:. 5498:. 5471:. 5449:. 5420:. 5390:: 5382:: 5360:. 5320:. 5293:. 5266:. 5239:. 5227:: 5208:. 5179:. 5150:. 5118:. 5082:. 5030:8 5020:n 4921:. 4907:. 4895:: 4869:. 4815:. 4790:. 4698:. 4671:. 4585:. 4544:y 4540:x 4437:n 4432:n 4426:n 4422:n 4417:n 4409:) 4405:( 4399:e 4397:) 4393:( 4391:a 4385:) 4381:( 4375:n 4370:G 4356:n 4349:n 4340:M 4336:M 4332:M 4323:M 3782:A 3777:A 3768:A 3669:A 3665:t 3660:0 3657:u 3655:) 3649:t 3647:( 3645:u 3638:t 3633:0 3630:u 3626:X 3618:t 3605:0 3602:u 3600:) 3594:t 3592:( 3590:u 3565:. 3560:0 3556:u 3552:= 3549:) 3546:0 3543:( 3540:u 3533:; 3530:) 3527:t 3524:( 3521:u 3518:A 3515:= 3512:) 3509:t 3506:( 3497:u 3488:{ 3473:X 3465:H 3448:, 3443:} 3438:0 3435:= 3432:) 3429:1 3426:( 3423:u 3420:= 3417:) 3414:0 3411:( 3408:u 3403:| 3398:) 3394:R 3390:; 3387:) 3384:1 3381:, 3378:0 3375:( 3372:( 3367:2 3363:H 3356:u 3351:{ 3346:= 3343:) 3340:A 3337:( 3334:D 3318:A 3308:L 3303:) 3301:R 3297:L 3293:X 3265:= 3262:t 3259:, 3256:) 3253:1 3250:, 3247:0 3244:( 3238:x 3233:, 3230:) 3227:x 3224:( 3219:0 3215:u 3211:= 3208:) 3205:x 3202:, 3199:t 3196:( 3193:u 3186:; 3183:0 3177:t 3174:, 3171:} 3168:1 3165:, 3162:0 3159:{ 3153:x 3148:, 3145:0 3142:= 3139:) 3136:x 3133:, 3130:t 3127:( 3124:u 3117:; 3114:0 3108:t 3105:, 3102:) 3099:1 3096:, 3093:0 3090:( 3084:x 3079:, 3076:) 3073:x 3070:, 3067:t 3064:( 3061:u 3056:2 3051:x 3043:= 3040:) 3037:x 3034:, 3031:t 3028:( 3025:u 3020:t 3009:{ 2992:t 2986:R 2943:S 2935:S 2927:S 2925:( 2923:G 2919:S 2914:A 2910:A 2908:. 2906:A 2897:X 2893:S 2886:S 2882:G 2873:k 2867:H 2863:G 2859:f 2850:H 2846:S 2842:k 2837:H 2833:S 2825:S 2821:) 2819:S 2817:( 2815:G 2811:S 2807:j 2798:S 2793:z 2784:S 2780:) 2778:S 2776:( 2774:G 2770:G 2762:S 2740:n 2735:z 2726:x 2721:) 2719:y 2717:( 2715:f 2711:x 2709:( 2707:f 2702:L 2690:x 2683:n 2678:z 2670:x 2661:a 2657:S 2650:S 2646:L 2642:S 2638:f 2634:L 2630:S 2626:S 2619:) 2617:y 2615:( 2613:f 2609:x 2607:( 2605:f 2599:y 2595:x 2590:S 2582:L 2578:f 2569:b 2567:∧ 2565:a 2561:S 2556:b 2552:S 2548:a 2544:S 2539:L 2531:S 2527:} 2525:a 2523:{ 2520:f 2514:a 2510:S 2504:L 2500:S 2496:f 2487:a 2483:a 2479:a 2470:L 2465:b 2461:a 2451:L 2447:b 2443:a 2432:L 2430:( 2415:. 2400:y 2396:x 2391:y 2381:x 2372:y 2368:x 2360:. 2356:0 2354:C 2350:. 2341:q 2337:p 2310:Q 2306:q 2301:y 2299:) 2291:( 2289:q 2279:Q 2275:Q 2271:x 2266:Q 2262:S 2258:x 2251:S 2244:Q 2240:S 2226:. 2215:. 2201:a 2197:c 2193:a 2189:b 2183:c 2179:b 2173:c 2169:a 2165:b 2161:a 2140:. 2129:. 2080:e 2076:e 2035:x 2031:} 2029:Z 2025:n 2021:x 2015:S 2011:x 2007:T 2001:A 1997:A 1993:S 1989:T 1985:S 1981:A 1966:S 1962:T 1958:S 1954:S 1950:T 1945:S 1941:T 1936:S 1932:T 1923:Z 1919:Z 1917:( 1911:Z 1907:Z 1905:( 1901:T 1897:S 1893:S 1889:T 1874:I 1870:y 1866:x 1861:y 1857:x 1851:y 1847:x 1838:I 1831:S 1819:S 1811:S 1804:S 1800:S 1777:~ 1773:S 1753:~ 1749:x 1742:S 1726:~ 1722:~ 1718:~ 1709:} 1707:a 1703:x 1699:S 1695:x 1691:~ 1681:S 1677:v 1673:u 1669:y 1665:x 1650:v 1646:u 1640:y 1636:x 1630:S 1626:S 1608:T 1604:S 1600:f 1585:T 1581:S 1570:f 1566:f 1561:1 1558:e 1554:0 1551:e 1549:( 1547:f 1542:f 1538:1 1535:e 1531:1 1528:e 1524:1 1521:S 1517:f 1513:0 1510:e 1508:( 1506:f 1502:0 1499:e 1495:0 1492:S 1488:f 1483:1 1480:S 1476:0 1473:S 1469:f 1464:S 1460:S 1449:f 1445:S 1441:b 1437:a 1431:. 1429:) 1427:b 1425:( 1423:f 1421:) 1419:a 1417:( 1415:f 1409:( 1407:f 1398:T 1394:S 1390:f 1336:S 1332:S 1328:S 1324:S 1309:A 1303:. 1301:A 1286:A 1273:, 1271:A 1255:A 1245:B 1241:b 1237:A 1233:a 1218:B 1214:A 1209:S 1205:B 1201:A 1189:S 1185:S 1181:S 1165:S 1161:S 1158:( 1152:S 1148:S 1144:} 1142:e 1138:S 1134:s 1128:s 1124:e 1120:s 1116:s 1112:e 1107:S 1102:S 1098:e 1089:S 1060:x 1056:f 1052:x 1047:S 1043:x 1039:f 1028:x 1024:x 1020:e 1015:S 1011:x 1007:e 999:S 977:. 947:. 935:F 927:F 851:. 848:a 844:a 840:a 835:a 790:) 788:c 784:b 780:a 776:c 772:b 768:a 766:( 762:S 758:c 754:b 750:a 737:S 733:S 729:S 716:S 695:e 688:t 681:v 198:x 194:y 188:y 184:x 164:z 160:y 156:x 152:) 150:z 146:y 142:x 138:z 134:y 130:x 128:( 124:) 122:y 118:x 116:( 104:y 100:x 66:. 20:)

Index

Semigroup theory

magmas
groups
magma
associativity
monoid
identity element
algebraic structure
set
associative
binary operation
multiplication
ordered pair
magmas
groups
commutative
matrix multiplication
analogous case of groups
monoid
identity element
strings
concatenation
strings
integers
integers
quasigroups
preserve from groups
division
a Cayley theorem for semigroups

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