scholarly journals An extension of properties of symmetric group to monoids and a pretorsion theory in a category of mappings

2019 ◽  
Vol 18 (12) ◽  
pp. 1950234 ◽  
Author(s):  
Alberto Facchini ◽  
Leila Heidari Zadeh
Keyword(s):  
Symmetric Group ◽  
Full Transformation ◽  
Transformation Monoid ◽  
Finite Set ◽  
Torsion Part

Several elementary properties of the symmetric group [Formula: see text] extend in a nice way to the full transformation monoid [Formula: see text] of all maps of the set [Formula: see text] into itself. The group [Formula: see text] turns out to be the torsion part of the monoid [Formula: see text]. That is, there is a pretorsion theory in the category of all maps [Formula: see text], [Formula: see text] an arbitrary finite set, in which bijections are exactly the torsion objects.

scholarly journals Sn-normal semigroups

1994 ◽  
Vol 37 (3) ◽  
pp. 471-476 ◽  
Author(s):  
I. Levi ◽  
R. B. McFadden
Keyword(s):  
Symmetric Group ◽  
Transformation Semigroup ◽  
Normal Closure ◽  
Full Transformation ◽  
Group Of Units ◽  
Full Transformation Semigroup ◽  
Finite Set ◽  
Normal Ideals

Certain subsemigroups of the full transformation semigroup Tn on a finite set of cardinality n are investigated, namely those subsemigroups S of Tn, which are normalised by the symmetric group on n elements, the group of units of Tn. The Sn-normal closure of an element of Tn is determined, and the structure of the Sn-normal ideals consisting of the members of Tn whose image contains at most r elements is studied.

scholarly journals Groups fixing graphas in switching classes

1982 ◽  
Vol 33 (1) ◽  
pp. 76-85
Author(s):  
Martin W. Liebeck
Keyword(s):  
Finite Group ◽  
Symmetric Group ◽  
Permutation Group ◽  
Abelian Groups ◽  
Finite Set ◽  
A Finite Group ◽  
Switching Class

AbstractA permutation group G on a finite set Ω is always exposable if whenever G stabilises a switching class of graphs on Ω, G fixes a graph in the switching class. Here we consider the problem: given a finite group G, which permutation representations of G are always exposable? We present solutions to the problem for (i) 2-generator abelian groups, (ii) all abelian groups in semiregular representations. (iii) generalised quaternion groups and (iv) some representations of the symmetric group Sn.

scholarly journals Square roots in finite full transformation semigroups

1982 ◽  
Vol 23 (2) ◽  
pp. 137-149 ◽  
Author(s):  
Mary Snowden ◽  
J. M. Howie
Keyword(s):  
Transformation Semigroup ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Necessary Condition ◽  
Square Root ◽  
Transformation Semigroups ◽  
Full Transformation ◽  
Square Roots ◽  
Finite Set ◽  
Necessary And Sufficient

Let X be a finite set and let (X) be the full transformation semigroup on X, i.e. the set of all mappings from X into X, the semigroup operation being composition of mappings. This paper aims to characterize those elements of (X) which have square roots. An easily verifiable necessary condition, that of being quasi-square, is found in Theorem 2, and in Theorems 4 and 5 we find necessary and sufficient conditions for certain special elements of (X). The property of being compatibly amenable is shown in Theorem 7 to be equivalent for all elements of (X) to the possession of a square root.

THE NATURAL ORDER FOR THE E-ORDER-PRESERVING TRANSFORMATION SEMIGROUPS

2012 ◽  
Vol 05 (03) ◽  
pp. 1250035 ◽  
Author(s):  
Huisheng Pei ◽  
Weina Deng
Keyword(s):  
Transformation Semigroup ◽  
Natural Order ◽  
Transformation Semigroups ◽  
Full Transformation ◽  
Minimal Elements ◽  
Full Transformation Semigroup ◽  
Finite Set

Let (X, ≤) be a totally ordered finite set, [Formula: see text] be the full transformation semigroup on X and E be an arbitrary equivalence on X. We consider a subsemigroup of [Formula: see text] defined by [Formula: see text] and call it the E-order-preserving transformation semigroup on X. In this paper, we endow EOPX with the so-called natural order ≤ and discuss when two elements in EOPX are related under this order, then determine those elements of EOPX which are compatible with ≤. Also, the maximal (minimal) elements are described.

scholarly journals Generating Functions for Permutations which Contain a Given Descent Set

10.37236/299 ◽  
2010 ◽  
Vol 17 (1) ◽  
Author(s):  
Jeffrey Remmel ◽  
Manda Riehl
Keyword(s):  
Symmetric Group ◽  
Generating Functions ◽  
Symmetric Function ◽  
Schur Functions ◽  
Permutation Statistics ◽  
Finite Set ◽  
Set Of Permutations ◽  
Descent Set ◽  
Positive Integers

A large number of generating functions for permutation statistics can be obtained by applying homomorphisms to simple symmetric function identities. In particular, a large number of generating functions involving the number of descents of a permutation $\sigma$, $des(\sigma)$, arise in this way. For any given finite set $S$ of positive integers, we develop a method to produce similar generating functions for the set of permutations of the symmetric group $S_n$ whose descent set contains $S$. Our method will be to apply certain homomorphisms to symmetric function identities involving ribbon Schur functions.

scholarly journals Centralising Monoids with Low-Arity Witnesses on a Four-Element Set

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1471
Author(s):  
Mike Behrisch ◽  
Edith Vargas-García
Keyword(s):  
The Other ◽  
Full Transformation ◽  
Group Operation ◽  
Binary Operations ◽  
Other Hand ◽  
Transformation Monoid ◽  
Element Set

As part of a project to identify all maximal centralising monoids on a four-element set, we determine all centralising monoids witnessed by unary or by idempotent binary operations on a four-element set. Moreover, we show that every centralising monoid on a set with at least four elements witnessed by the Maľcev operation of a Boolean group operation is always a maximal centralising monoid, i.e., a co-atom below the full transformation monoid. On the other hand, we also prove that centralising monoids witnessed by certain types of permutations or retractive operations can never be maximal.

Idempotent generators in finite full transformation semigroups

1978 ◽  
Vol 81 (3-4) ◽  
pp. 317-323 ◽  
Author(s):  
J. M. Howie
Keyword(s):  
Transformation Semigroups ◽  
Minimal Set ◽  
Full Transformation ◽  
Generating Set ◽  
Finite Set

SynopsisIt was proved by Howie in 1966 that , the semigroup of all singular mappings of a finite set X into itself, is generated by its idempotents. Implicit in the method of proof, though not formally stated, is the result that if |X| = n then the n(n – 1) idempotents whose range has cardinal n – 1 form a generating set for. Here it is shown that if n ≧ 3 then a minimal set M of idempotent generators for contains ½n(n–1) members. A formula is given for the number of distinct sets M.

scholarly journals HALL'S CONDITION AND IDEMPOTENT RANK OF IDEALS OF ENDOMORPHISM MONOIDS

2008 ◽  
Vol 51 (1) ◽  
pp. 57-72 ◽  
Author(s):  
R. Gray
Keyword(s):  
Simple Semigroup ◽  
Analogous Result ◽  
Direct Consequence ◽  
Full Transformation ◽  
Generating Set ◽  
Endomorphism Monoids ◽  
Idempotent Rank ◽  
Transformation Monoid ◽  
Hall's Condition ◽  
Property Holding

AbstractIn 1990, Howie and McFadden showed that every proper two-sided ideal of the full transformation monoid $T_n$, the set of all maps from an $n$-set to itself under composition, has a generating set, consisting of idempotents, that is no larger than any other generating set. This fact is a direct consequence of the same property holding in an associated finite $0$-simple semigroup. We show a correspondence between finite $0$-simple semigroups that have this property and bipartite graphs that satisfy a condition that is similar to, but slightly stronger than, Hall's condition. The results are applied in order to recover the above result for the full transformation monoid and to prove the analogous result for the proper two-sided ideals of the monoid of endomorphisms of a finite vector space.

scholarly journals Affine symmetric group

2021 ◽  
Vol 4 (1) ◽  
pp. 3
Author(s):  
Joel Brewster Lewis
Keyword(s):  
Representation Theory ◽  
Symmetric Group ◽  
Mathematical Structure ◽  
Number Line ◽  
Geometric Description ◽  
Generators And Relations ◽  
Higher Dimensional ◽  
Finite Set ◽  
Finite Symmetric Group

The affine symmetric group is a mathematical structure that describes the symmetries of the number line and the regular triangular tesselation of the plane, as well as related higher dimensional objects. It is an infinite extension of the symmetric group, which consists of all permutations (rearrangements) of a finite set. In additition to its geometric description, the affine symmetric group may be defined as the collection of permutations of the integers (..., −2, −1, 0, 1, 2, ...) that are periodic in a certain sense, or in purely algebraic terms as a group with certain generators and relations. These different definitions allow for the extension of many important properties of the finite symmetric group to the infinite setting, and are studied as part of the fields of combinatorics and representation theory.

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