Editing Propositional variable (section)

{{short description|Variable that can either be true or false}}
In [[mathematical logic]], a '''propositional variable''' (also called a '''sentence letter,<ref name=":13">{{Cite book |last=Howson |first=Colin |author-link=Colin Howson |title=Logic with trees: an introduction to symbolic logic |date=1997 |publisher=Routledge |isbn=978-0-415-13342-5 |location=London; New York |pages=5}}</ref>''' '''sentential variable,''' or '''sentential letter''') is an input [[variable (mathematics)|variable]] (that can either be '''true''' or '''false''') of a [[truth function]]. Propositional variables are the basic building-blocks of [[propositional formula]]s, used in [[propositional logic]] and [[higher-order logic]]s.