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math.GR2021
Variations on the Post Correspondence Problem for free groups
Laura Ciobanu, Alan D. Logan
The Post Correspondence Problem is a classical decision problem about equalisers of free monoid homomorphisms. We prove connections between several variations of this classical pro…
math.GR2020
Fixed points and stable images of endomorphisms for the free group of rank two
Laura Ciobanu, Alan D. Logan
We give an algorithm which computes the fixed subgroup and the stable image for any endomorphism of the free group of rank two , answering for a question posed by Stalli…
math.GR2020
The Post Correspondence Problem and equalisers for certain free group and monoid morphisms
Laura Ciobanu, Alan D. Logan
A marked free monoid morphism is a morphism for which the image of each generator starts with a different letter, and immersions are the analogous maps in free groups. We show that…