We investigate topological properties of subsets S of the real plane expressed by rst order logic sentences in the language of the reals aug mented with a binary relation symbol for S Two sets are called topo logically elementary equivalent if they have the same such rst order topological properties The contribution of this paper is a natural and e ective characterization of topological element...

in this paper, using pre-semi-open l-sets and their inequality, a new notion of ps-compactness is introduced in l-topological spaces, where l is a complete de morgan algebra. this notion does not depend on the structure of the basis lattice l and l does not need any distributivity.

Ma consider the problem of answering pa r t o f quest ions and quest ions about over lap in p a r t i t i o n i n g s t r u c t u r e s . which is of importance in A . I . systems knowledgeable about pa r t s r e l a t i o n s h i p s , set i nc lus ion r e l a t i o n s h i p s or taxonomies of types in an e a r l i e r paper 1t was noted that the problem of e x t r a c t i n g informat ion fr...