scholarly journals Growth sequences of finite semigroups

1987 ◽  
Vol 43 (1) ◽  
pp. 16-20 ◽  
Author(s):  
James Wiegold ◽  
H. Lausch
Keyword(s):  
Real Number ◽  
Finite Semigroup ◽  
Piecewise Linear ◽  
The Other ◽  
Direct Power ◽  
Growth Sequence ◽  
Group Of Units ◽  
Number Of Generators ◽  
Finite Semigroups ◽  
Minimum Number

AbstractThe growth sequence of a finite semigroup S is the sequence {d(Sn)}, where Sn is the nth direct power of S and d stands for minimum generating number. When S has an identity, d(Sn) = d(Tn) + kn for all n, where T is the group of units and k is the minimum number of generators of S mod T. Thus d(Sn) is essentially known since d(Tn) is (see reference 4), and indeed d(Sn) is then eventually piecewise linear. On the other hand, if S has no identity, there exists a real number c > 1 such that d(Sn) ≥ cn for all n ≥ 2.

scholarly journals Growth sequences of finite groups V

1981 ◽  
Vol 31 (3) ◽  
pp. 374-375 ◽  
Author(s):  
D. Meier ◽  
James Wiegold
Keyword(s):  
Finite Group ◽  
Automorphism Group ◽  
Finite Groups ◽  
The Other ◽  
Direct Power ◽  
Easy Proof ◽  
Number Of Generators ◽  
Other Hand ◽  
Minimum Number

AbstractA short and easy proof that the minimum number of generators of the nth direct power of a non-trival finite group of order s having automorphism group of order a is more than logsn + logsa, n > 1. On the other hand, for non-abelian simple G and large n, d(Gn) is within 1 + e of logsn + logsa.

scholarly journals Growth sequences of finite groups

1974 ◽  
Vol 17 (2) ◽  
pp. 133-141 ◽  
Author(s):  
James Wiegold
Keyword(s):  
Characteristic Property ◽  
Simple Consequence ◽  
Direct Power ◽  
Growth Sequence ◽  
Finitely Generated Groups ◽  
Number Of Generators ◽  
Special Cases ◽  
Different Types ◽  
Minimum Number ◽  
Positive Integers

During his investigation of the possible non-Hopf kernels for finitely generated groups in [1], Dey proves that the minimum number of generators d(Gn) of the n-th direct power Gn of a non-trival finite group G tends to infinity with n. This has prompted me to ask the question: what are the ways in which the sequence {d(Gn)} can tend to infinity? Let us call this the growth sequence for G; it is evidently monotone non-decreasing, and is at least logarithmic (Theorem 2.1). This paper is devoted to a proof that, broadly speaking, there are two different types of behaviour. If G has non-trivial abelian images (the imperfect case, § 3), then the growth sequence of G is eventually an arithmetic progression with common difference d(G/G'). In special cases (Theorem 5.2) the initial behaviour can be quite nasty. Our arguments in § 3 are totally elementary. If G has only trivial abelian images (the perfect case,§ 4), then the growth sequence of G is eventually bounded above by a sequence that grows logarithmically. It is a simple consequence of this fact that there are arbitrarily long blocks of positive integers on which the growth sequence takes constant values. This is a characteristic property of perfect groups, and indeed it was this feature in the growth sequences of large alternating groups (which I found by using ad hoc permutational arguments) that attracted me to the problem in the first place. The discussion of the perfect case rests on the lovely paper of Hall [2], which was brought to my notice by M. D. Atkinson.

Growth sequences of 2-generator simple groups

1993 ◽  
Vol 123 (5) ◽  
pp. 839-855 ◽  
Author(s):  
V. N. Obraztsov
Keyword(s):  
Simple Groups ◽  
Direct Power ◽  
Number Of Generators ◽  
Minimum Number

SynopsisA study is made of the minimum number of generators of the n-th direct power of certain 2-generator groups.

PROFINITE METHODS IN SEMIGROUP THEORY

2002 ◽  
Vol 12 (01n02) ◽  
pp. 137-178 ◽  
Author(s):  
PASCAL WEIL
Keyword(s):  
Finite Semigroup ◽  
Finite Algebra ◽  
Semigroup Theory ◽  
The Other ◽  
Finite Semigroups ◽  
Compact Semigroups ◽  
Projective Limits ◽  
The Way

Many recent results in finite semigroup theory make use of profinite methods, that is, they rely on the study of certain infinite, compact semigroups which arise as projective limits of finite semigroups. These ideas were introduced in semigroup theory in the 1980s, first to describe pseudovarieties in terms of so-called pseudo-identities: this is Reiterman's theorem, which can be viewed as the (much more complex) finite algebra analogue of Birkhoff's variety theorem. Soon, these methods were used in conjunction with virtually all the other approaches of finite semigroups, notably to study the decidability of product pseudovarieties. This paper surveys the contribution of profinite methods and the way they enriched and modified finite semigroup theory.

scholarly journals Growth sequences of finitely generated groups II

1989 ◽  
Vol 40 (2) ◽  
pp. 323-329 ◽  
Author(s):  
A.G.R. Stewart ◽  
James Wiegold
Keyword(s):  
Finitely Generated ◽  
Direct Power ◽  
Finitely Generated Groups ◽  
Number Of Generators ◽  
Minimum Number

A study is made of the minimum number of generators of the n-th direct power of certain finitely generated groups.

Undecidability of the identity problem for finite semigroups

1992 ◽  
Vol 57 (1) ◽  
pp. 179-192 ◽  
Author(s):  
Douglas Albert ◽  
Robert Baldinger ◽  
John Rhodes
Keyword(s):  
Word Problem ◽  
Finite Semigroup ◽  
Identity Problem ◽  
Finite Semigroups ◽  
Or Groups ◽  
Finite Set ◽  
Variety Of Semigroups ◽  
Finite Products

In 1947 E. Post [28] and A. A. Markov [18] independently proved the undecidability of the word problem (or the problem of deducibility of relations) for semigroups. In 1968 V. L. Murskil [23] proved the undecidability of the identity problem (or the problem of deducibility of identities) in semigroups.If we slightly generalize the statement of these results we can state many related results in the literature and state our new results proved here. Let V denote either a (Birkhoff) variety of semigroups or groups or a pseudovariety of finite semigroups. By a very well-known theorem a (Birkhoff) variety is defined by equations or equivalently closed under substructure, surmorphisms and all products; see [7]. It is also well known that V is a pseudovariety of finite semigroups iff V is closed under substructure, surmorphism and finite products, or, equivalently, determined eventually by equations w1 = w1′, w2 = w2′, w3 = w3′,… (where the finite semigroup S eventually satisfies these equations iff there exists an n, depending on S, such that S satisfies Wj = Wj′ for j ≥ n). See [8] and [29]. All semigroups form a variety while all finite semigroups form a pseudovariety.We now consider a table (see the next page). In it, for example, the box denoting the “word” (identity) problem for the psuedovariety V” means, given a finite set of relations (identities) E and a relation (identity) u = ν, the problem of whether it is decidable that E implies u = ν inside V.

The Cookie Monster Problem

2015 ◽  
Author(s):  
Leigh Marie Braswell ◽  
Tanya Khovanova
Keyword(s):  
Real Number ◽  
Problem Solver ◽  
Minimum Number

This chapter examines the problem of the “Cookie Monster number.” In 2002, Cookie Monster® appeared in the book The Inquisitive Problem Solver by Vaderlind, Guy, and Larson, where the hungry monster wants to empty a set of jars filled with various numbers of cookies. The Cookie Monster number is the minimum number of moves Cookie Monster must use to empty all the jars. The chapter analyzes this problem by first introducing known general algorithms and known bounds for the Cookie Monster number. It then explicitly finds the Cookie Monster number for jars containing cookies in the Fibonacci, Tribonacci, n-nacci, and Super-n-nacci sequences. The chapter also constructs sequences of k jars such that their Cookie Monster numbers are asymptotically rk, where r is any real number, 0 ≤ r ≤ 1.

scholarly journals Card-Based Cryptographic Logical Computations Using Private Operations

2020 ◽  
Author(s):  
Hibiki Ono ◽  
Yoshifumi Manabe
Keyword(s):  
Cryptographic Protocols ◽  
The Other ◽  
General Logic ◽  
Private Values ◽  
Minimum Number ◽  
Logic Functions ◽  
Logical Functions

Abstract This paper proposes new card-based cryptographic protocols to calculate logic functions with the minimum number of cards using private operations under the semi-honest model. Though various card-based cryptographic protocols were shown, the minimum number of cards used in the protocol has not been achieved yet for many problems. Operations executed by a player where the other players cannot see are called private operations. Private operations have been introduced in some protocols to solve a particular problem or to input private values. However, the effectiveness of introducing private operations to the calculation of general logic functions has not been considered. This paper introduces three new private operations: private random bisection cuts, private reverse cuts, and private reveals. With these three new operations, we show that all of AND, XOR, and copy protocols are achieved with the minimum number of cards by simple three-round protocols. This paper then shows a protocol to calculate any logical functions using these private operations. Next, we consider protocols with malicious players.

scholarly journals Growth sequence of globally idemportent semigroups

1990 ◽  
Vol 48 (1) ◽  
pp. 87-88 ◽  
Author(s):  
György Pollák
Keyword(s):  
Finite Semigroup ◽  
Identity Element ◽  
Growth Sequence

AbstractThe n–th member of the growth sequence of a globally idempotent finite semigroup without identity element is at least 2n. (This had been conjectured by J. Wiegold.)

scholarly journals Commutator Length of Finitely Generated Linear Groups

2008 ◽  
Vol 2008 ◽  
pp. 1-5
Author(s):  
Mahboubeh Alizadeh Sanati
Keyword(s):  
Finite Group ◽  
Upper Bound ◽  
Quadratic Polynomial ◽  
Linear Groups ◽  
Number Of Generators ◽  
Derived Subgroup ◽  
Finite Linear Group ◽  
Minimum Number ◽  
Commutator Length ◽  
Finite Linear

The commutator length “” of a group is the least natural number such that every element of the derived subgroup of is a product of commutators. We give an upper bound for when is a -generator nilpotent-by-abelian-by-finite group. Then, we give an upper bound for the commutator length of a soluble-by-finite linear group over that depends only on and the degree of linearity. For such a group , we prove that is less than , where is the minimum number of generators of (upper) triangular subgroup of and is a quadratic polynomial in . Finally we show that if is a soluble-by-finite group of Prüffer rank then , where is a quadratic polynomial in .

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