Semilattices with a unary operation are treated. We set a simple condition such that every semilattice with a unary operation satisfying it is a lattice. If one more simple condition is satisfied, this lattice is an ortholattice where the unary operationis a orthocomplementation.
Semilattices with a unary operation are treated. We set a simple condition such that every semilattice with a unary operation satisfying it is a lattice. If one more simple condition is satisfied, this lattice is an ortholattice where the unary operationis a orthocomplementation. (en)