Join-semilattices whose sections are residuated po-monoids

Chajda, Ivan ; Kühr, Jan

Czechoslovak Mathematical Journal, Tome 58 (2008) no. 4, pp. 1107-1127.

Résumé

We generalize the concept of an integral residuated lattice to join-semilattices with an upper bound where every principal order-filter (section) is a residuated semilattice; such a structure is called a {\it sectionally residuated semilattice}. Natural examples come from propositional logic. For instance, implication algebras (also known as Tarski algebras), which are the algebraic models of the implication fragment of the classical logic, are sectionally residuated semilattices such that every section is even a Boolean algebra. A similar situation rises in case of the Łukasiewicz multiple-valued logic where sections are bounded commutative BCK-algebras, hence MV-algebras. Likewise, every integral residuated (semi)lattice is sectionally residuated in a natural way. We show that sectionally residuated semilattices can be axiomatized as algebras $(A,r,\rightarrow ,\rightsquigarrow,1)$ of type $\langle 3,2,2,0\rangle $ where $(A,\rightarrow ,\rightsquigarrow,1)$ is a $\{\rightarrow ,\rightsquigarrow ,1\}$-subreduct of an integral residuated lattice. We prove that every sectionally residuated {\it lattice} can be isomorphically embedded into a residuated lattice in which the ternary operation $r$ is given by $r(x,y,z)=(x\cdot y)ěe z$. Finally, we describe mutual connections between involutive sectionally residuated semilattices and certain biresiduation algebras.

Détail

Classification : 06D35, 06F05, 06F35
Keywords: residuated lattice; residuated semilattice; biresiduation algebra; pseudo-MV-algebra; sectionally residuated semilattice; sectionally residuated lattice