This document discusses the basics of propositional logic. It defines propositions or statements as the basic units of propositional logic. Compound propositions are formed when simple propositions are connected with logical connectives like "and" and "or". A proposition must always be able to be validated as true or false. It provides examples of true, false, and non-valid propositions. Propositional variables are used to represent unspecified statements. Logical equivalences are compound propositions that have the same logical content. Predicates are parts of statements that can be affected by variables. Quantifiers like universal, existential, and uniqueness are used to represent logical quantities.