A special case is a mathematical object, statement, or formula obtained from a more general one by imposing additional conditions or particular parameter values (Rosenberg 2019). For example, a square is a special case of a rectangle in which adjacent sides have equal lengths. The Pythagorean theorem is the special case of the law of cosines in which the included angle is a right angle.
Verifying a statement in a special case alone does not establish the general statement.
