Use this tag for questions related to reasoning obtained by manipulating equations with free variables.
Algebraic logic is reasoning obtained by manipulating equations with free variables.
What is now usually called classical algebraic logic focuses on identification and algebraic description of models for the study of (1) various logics in the form of classes of algebras that constitute the algebraic semantics for those deductive systems and (2) connected problems like representation and duality. Well known results, such as the representation theorem in boolean-algebra and Stone duality, fall under the umbrella of classical algebraic logic.
Work in the more recent abstract algebraic logic focuses on the process of algebraization itself, for example, classification of various forms of algebraizability using the Leibniz operator.