A rule of inference in Propositional logic. Used to break up a disjunctive statement. Like this:
(I am using ^ for 'or', not xor).
P^Q
~P
Therefore, Q
I have an apple or an orange.
I don't have an apple.
Therefore, I have an orange.
Abruviated as DS.
See also: Modus Ponens, Modus Tollens, And Hypothetical Syllogism. | 
