Reducibility of pointlike problems

被引：5

作者：

Almeida, J. ^{[1
,2
]}

Costa, J. C. ^{[3
,4
]}

Zeitoun, M. ^{[5
]}

机构：

[1] Univ Porto, Ctr Matemat, Rua Campo Alegre 687, P-4169007 Oporto, Portugal

[2] Univ Porto, Fac Ciencias, Dept Matemat, Rua Campo Alegre 687, P-4169007 Oporto, Portugal

[3] Univ Minho, Ctr Matemat, Campus Gualtar, P-4700320 Braga, Portugal

[4] Univ Minho, Dept Matemat & Aplicacoes, Campus Gualtar, P-4700320 Braga, Portugal

[5] Univ Bordeaux, LaBRI, UMR 5800, F-33400 Talence, France

来源：

SEMIGROUP FORUM | 2017年 / 94卷 / 02期

关键词：

Pseudovariety; Profinite semigroup; Pointlike set; Regular language; Aperiodic semigroup; TAMENESS;

D O I：

10.1007/s00233-015-9769-2

中图分类号：

O1 [数学];

学科分类号：

0701 ; 070101 ;

摘要：

We show that the pointlike and the idempotent pointlike problems are reducible with respect to natural signatures in the following cases: the pseudovariety of all finite semigroups in which the order of every subgroup is a product of elements of a fixed set pi of primes; the pseudovariety of all finite semigroups in which every regular J-class is the product of a rectangular band by a group from a fixed pseudovariety of groups that is reducible for the pointlike problem, respectively graph reducible. Allowing only trivial groups, we obtain omega-reducibility of the pointlike and idempotent pointlike problems, respectively for the pseudovarieties of all finite aperiodic semigroups (A) and of all finite semigroups in which all regular elements are idempotents (DA).

引用

页码：325 / 335

页数：11