Abstract:Relative versions of many important theorems on cardinal invariants of topological spaces are formulated and proved on the basis of a general technical result, which provides an algorithm for such proofs. New relative cardinal invariants are defined, and open problems are discussed.
Keywords: Lindel\"of space, Souslin number, spread, extent, pseudocharacter, relative cardinal invariant
AMS Subject Classification: Primary 54A25; Secondary 54D20