The logical operation exclusive disjunction, also called exclusive or, (symbolized XOR or EOR), is a type of logical disjunction on two operands that results in a value of ?true? if and only if exactly one of the operands has a value of ?true?. See Stanford Encyclopedia of Philosophy, article [LINK: http://plato.stanford.edu/entries/disjunction/] Disjunction Put differently, exclusive disjunction is a logical operation on two logical values, typically the values of two propositions, that produces a value of true just in cases where the truth value of the operands differ. Truth table The truth table of p, mathrm, q (also written as p oplus q, or p neq q) is as follows: Note the three-way symmetry of the outcomes: The identity o