Quasi-abelian and quasi-solvable regular semigroups

Autor: Brunetto Piochi

Publikováno v: Le Matematiche, Vol 51, Iss 3, Pp 167-182 (1996)

In this note quasi-abelian semigroups are studied and it is proved that they form an e-variety of orthodox semigroups. More, quasi-abelian regular Bruck-Reilly monoids are characterized as extensions of monoids which are (reverse) semidirect products

Externí odkaz: https://doaj.org/article/8d02cf9c8b6f45d0bfee59634d0da33f

Amalgams of finite inverse semigroups

Autor: Brunetto Piochi, Alessandra Cherubini, John Meakin

Publikováno v: Journal of Algebra. 285(2):706-725

We show that the word problem is decidable for an amalgamated free product of finite inverse semigroups (in the category of inverse semigroups). This is in contrast to a recent result of M. Sapir that shows that the word problem for amalgamated free

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::32e5b8996bb65f01b18c62861e634469

Amalgams of free inverse semigroups

Autor: Brunetto Piochi, John Meakin, Alessandra Cherubini

Publikováno v: Semigroup Forum. 54:199-220

We study inverse semigroup amalgams of the formS * U T whereS andT are free inverse semigroups andU is an arbitrary finitely generated inverse subsemigroup ofS andT. We make use of recent work of Bennett to show that the word problem is decidable for

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::fe295235a014dbaebb1d19fe36df676a
https://doi.org/10.1007/bf02676602

A finiteness condition for semigroups which generalizes Green-Rees' theorem

Autor: Brunetto Piochi

Publikováno v: Semigroup Forum. 50:301-306

LetS be a finitely generated semigroup. ThenS is finite if every finitely generated subgroup ofS is finite and, for some integerm≥1, for everym-tuplex 1,x 2,…x m of elements ofS there exist an integeri: 1≤i≤m and an integer ρ>1 such that:x i

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::0e1e6868465d0e31ae4c4ca8edb258c8
https://doi.org/10.1007/bf02573527

On the length of shortest 2-collapsing words

Autor: Brunetto Piochi, Andrzej Kisielewicz, Alessandra Cherubini

Publikováno v: Discrete Mathematics and Theoretical Computer Science
Discrete Mathematics and Theoretical Computer Science, DMTCS, 2009, 11 (1), pp.33--44

Automata, Logic and Semantics
Given a word w over a finite alphabet Sigma and a finite deterministic automaton A = < Q,Sigma,delta >, the inequality vertical bar delta(Q,w)vertical bar

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0bb679cc11a039001265c862bbc1f1f2
https://hal.inria.fr/hal-00988185/document