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math.GR2020
The Karoubi envelope of the mirage of a subshift
Alfredo Costa, Benjamin Steinberg
We study a correspondence associating to each subshift of a subcategory of the Karoubi envelope of the free profinite semigroup generated by . The o…
math.GR2019
Bases for pseudovarieties closed under bideterministic product
Alfredo Costa, Ana Escada
We show that if is a semigroup pseudovariety containing the finite semilattices and contained in , then it has a basis of pseudoidentities between finite…
math.GR2018
Profinite topologies
Jorge Almeida, Alfredo Costa
Profinite semigroups are a generalization of finite semigroups that come about naturally when one is interested in considering free structures with respect to classes of finite sem…