FACETS OF INTENSIONALITY

The goal of this paper is to introduce the reader distinction between intensional and extensional as a different approaches meaning. We will argue that despite common belief, aspects mathematical notions can be, in fact have been successfully described mathematics. One for us particularly interesting notion deduction depicted general proof theory. Our considerations result defending a) importance rule-based semantical approach b) position according which non-reductive somewhat circular explanations play an essential role describing intensionality