An arbitrary orthoposet E is shown to be isomorphic to (ε, C,c ), ε being a subbasis of a Hausdorff topological space S satisfying 1) S ∈ ε, 2) α ∈ αc ∈ ε, and 3) every covering of S by elements of ε possesses an at most ...
After making a brief survey of results on finite concrete logics obtained during the last 16 years, we present new ones due to the authors. We especially concentrate on developing the duality theory and handling problems ...