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math.GM2016
The lattice of congruence lattices of algebras on a finite set
Danica Jakubíková-Studenovská, Reinhard Pöschel, Sándor Radeleczki
The congruence lattices of all algebras defined on a fixed finite set ordered by inclusion form a finite atomistic lattice . We describe the atoms and coatoms. Each…
math.CO2016
Permutation groups, pattern involvement, and Galois connections
Erkko Lehtonen, Reinhard Pöschel
There is a connection between permutation groups and permutation patterns: for any subgroup of the symmetric group and for any , the set of -permutatio…