 In propositional logic, disjunction is used to create a compound proposition which is false, only if both propositions or disjuncts in it are false. It closely resembles OR in natural language and is represented by the small letter V going back to Latin VEL. Here is a true example. Earth is a planet of the solar system or a satellite of the Sun. If both disjuncts are true, as in our case, the disjunction is true too. But even if P is false and the Earth is not a planet, and Q is true, P or Q is true too. And similarly, if Q is false and the Earth is not a satellite of the Sun, the whole proposition Earth is a planet or not a satellite of the Sun is still true. Only if both propositions are false, that is, Earth is not a planet or not a satellite of the Sun, P or Q is false. Thus, the truth value of a complex proposition linked with OR is determined by the truth values of its component propositions. It is true if at least one disjunct is true. This type of disjunction is referred to as inclusive disjunction. A stricter type of disjunction often referred to as exclusive disjunction or short XOR is true only if one of the disjuncts is true. It is symbolized by an encircled V. In natural language, XOR resembles either P or Q, whereas inclusive OR can be represented best as P or also Q.