Fractal construction of an atomic Archimedean effect algebra with non-atomic subalgebra of sharp elements Vladimír Olejček (2012) Kybernetika Does there exist an atomic Archimedean lattice effect algebra with non-atomic subalgebra of sharp elements? An affirmative answer to this question is given.
Functional completeness in pseudocomplemented de Morgan algebras Klaus Denecke (1987) Beiträge zur Algebra und Geometrie = Contributions to algebra and geometry