6 papers · 1 filter
Classifications of quasitrivial semigroups
Jimmy Devillet, Jean-Luc Marichal, Bruno Teheux
We investigate classifications of quasitrivial semigroups defined by certain equivalence relations. The subclass of quasitrivial semigroups that preserve a given total ordering is…
Invariance in a class of operations related to weighted quasi-geometric means
Jimmy Devillet, Janusz Matkowski
Let be an interval that is closed with respect to the multiplication. The operations of the form \begin{equation*} C_{f,g}…
A new invariance identity and means
Jimmy Devillet, Janusz Matkowski
The invariance identity involving three operations of the form \begin{equation*} D_{f,g}\left( x,y\right) =\left( f\circ g\right) ^{-1}\left( f\lef…
Characterizations of biselective operations
Jimmy Devillet, Gergely Kiss
Let be a nonempty set and let . We say that a binary operation is -selective if for all $x…
Associative, idempotent, symmetric, and order-preserving operations on chains
Jimmy Devillet, Bruno Teheux
We characterize the associative, idempotent, symmetric, and order-preserving operations on (finite) chains in terms of properties of (the Hasse diagram of) their associated semilat…
Bisymmetric and quasitrivial operations: characterizations and enumerations
Jimmy Devillet
We investigate the class of bisymmetric and quasitrivial binary operations on a given set and provide various characterizations of this class as well as the subclass of bisymme…