Abstract

We focus attention on certain elements of a double Heyting algebra, called core points. These core points may be viewed as a generalization of com- plemented elements. While some lattices may contain only 0,1 as the com- plemented elements, we show that in general there are more core points, enough to enable the expansion theorem mentioned below for dissectable lattices. The set of all core points is called the core. The sublattice gener- ated by the core is called the exocenter