Until 1980, there was no such subgroup as ‘infinite permutation groups’, according to the Mathematics Subject Classification: permutation groups were assumed to be finite. There were a few papers, for example [10, 62], and a set of lecture notes by Wielandt [72], from the 1950s. Now, however, there are far more papers on the topic than can possibly be summarised in an article like this one. I s...

for two normal edge-transitive cayley graphs on groups h and k which have no common direct factor and gcd(jh=h ′j; jz(k)j) = 1 = gcd(jk=k ′j; jz(h)j), we consider four standard products of them and it is proved that only tensor product of factors can be normal edge-transitive.

Let S be a set of transpositions generating the symmetric group Sn (n ≥ 5). The transposition graph of S is defined to be the graph with vertex set {1, . . . , n}, and with vertices i and j being adjacent in T (S) whenever (i, j) ∈ S. In the present note, it is proved that two transposition graphs are isomorphic if and only if the corresponding two Cayley graphs are isomorphic. It is also prove...

Interval parking functions (IPFs) are a generalization of ordinary in which each car is willing to park only fixed interval spaces. Each function can be expressed as pair (a,b), where and b dual function. We say that permutations (x,y) reachable if there an IPF (a,b) such x,y the outcomes a,b, respectively, functions. Reachability reflexive antisymmetric, but not general transitive. prove its t...

It is well known that lattice-valued rough sets are important branches of fuzzy sets. The axiomatic characterization and related topology the main research directions For L=(L,⊛), a complete co-residuated lattice (CCRL), Qiao recently defined an L-fuzzy lower approximation operator (LFLAO) on basis relation. In this article, we give further study Qiao’s LFLAO around induced L-topology. Firstly,...

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii CHAPTER 1. HISTORICAL BACKGROUND . . . . . . . . . . . . . . . . . 1 1.1 Early Historical Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Resolvent Polynomials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 More Recent Developments . . . . . . . . . . . . . . . . . ....

All known finite sharply 4-transitive permutation sets containing the identity are groups, namely S4, S5, A6 and the Mathieu group of degree 11. We prove that a sharply 4-transitive permutation set on 11 elements containing the identity must necessarily be the Mathieu group of degree 11. The proof uses direct counting arguments. It is based on a combinatorial property of the involutions in the ...

It is well known that many two-dimensional products of modal logics with at least one ‘transitive’ (but not ‘symmetric’) component lack the product finite model property. Here we show that products of two ‘transitive’ logics (such as, e.g., K4 ×K4, S4 × S4, Grz×Grz and GL×GL) do not have the (abstract) finite model property either. These are the first known examples of 2D modal product logics w...