Displaying similar documents to “The ordering of commutative terms”

Definability for equational theories of commutative groupoids

Jaroslav Ježek (2012)

Czechoslovak Mathematical Journal

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We find several large classes of equations with the property that every automorphism of the lattice of equational theories of commutative groupoids fixes any equational theory generated by such equations, and every equational theory generated by finitely many such equations is a definable element of the lattice. We conjecture that the lattice has no non-identical automorphisms.

Polypodic codes

Symeon Bozapalidis, Olympia Louscou-Bozapalidou (2002)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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Word and tree codes are studied in a common framework, that of polypodes which are sets endowed with a substitution like operation. Many examples are given and basic properties are examined. The code decomposition theorem is valid in this general setup.

Varieties of idempotent slim groupoids

Jaroslav Ježek (2007)

Czechoslovak Mathematical Journal

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Idempotent slim groupoids are groupoids satisfying x x x ̄ and x ( y z ) x ̄ z . We prove that the variety of idempotent slim groupoids has uncountably many subvarieties. We find a four-element, inherently nonfinitely based idempotent slim groupoid; the variety generated by this groupoid has only finitely many subvarieties. We investigate free objects in some varieties of idempotent slim groupoids determined by permutational equations.