scholarly journals Lattice isomorphisms of free products of inverse semigroups

1984 ◽  
Vol 89 (2) ◽  
pp. 280-290 ◽  
Author(s):  
Peter R Jones
Author(s):  
Karl Auinger

It is shown that the free product of two residually finite combinatorial strict inverse semigroups in general is not residually finite. In contrast, the free product of a residually finite combinatorial strict inverse semigroup and a semilattice is residually finite.


1976 ◽  
Vol 15 (1) ◽  
pp. 117-124 ◽  
Author(s):  
G.B. Preston

Let Si, i ∈ I, be a set of semigroups such that Si ∩ Sj = U, if i ≠ j, and such that U is a unitary subsemi-group of Si for each i in I. The semigroup amalgam [{Si | i ∈ I}; U] determined by this system is the partial groupoid G = USi in which a product of two elements is defined if and only if they both belong to the same Si and their product is then taken as their product in Si. In 1962, J.M. Howie showed that the amalgam G is embeddable in the free product of the Si, amalgamating U. To prove this result it suffices to find any semigroup in which G can be embedded. In this paper, by taking convenient representations of the Si, adapting a method recently (1975) used by T.E. Hall for inverse semigroups, we provide a short method of constructing such a semigroup.


1992 ◽  
Vol 120 (3-4) ◽  
pp. 191-197 ◽  
Author(s):  
Pedro V. Silva

SynopsisThis note discusses primeness for semigroup rings of semigroups satisfying a certain condition, weaker than the u.p. property. These semigroups include free products of semigroups, semigroups presented by a single relator and at least three generators, and free inverse semigroups of infinite rank.


1991 ◽  
Vol 33 (3) ◽  
pp. 373-387 ◽  
Author(s):  
Peter R. Jones ◽  
Stuart W. Margolis ◽  
John Meakin ◽  
Joseph B. Stephen

Let S and T be inverse semigroups. Their free product S inv T is their coproduct in the category of inverse semigroups, defined by the usual commutative diagram. Previous descriptions of free products have been based, like that for the free product of groups, on quotients of the free semigroup product S sgp T. In that framework, a set of canonical forms for S inv T consists of a transversal of the classes of the congruence associated with the quotient. The general result [4] of Jones and previous partial results [3], [5], [6] take this approach.


1979 ◽  
Vol 27 (3) ◽  
pp. 358-364 ◽  
Author(s):  
P. R. Jones

AbstractThe free product of two Hopfian groups (in the category of groups) need not be Hopfian. We prove, by elementary methods, that the free product of two simple Hopfian inverse semigroups is Hopfian. In particular the free product of any two Hopfian groups, in the category of inverse semigroups, is again Hopfian. In fact the same is true in the category of all semigroups.


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