What is another word for open sentences?
Pronunciation: [ˈə͡ʊpən sˈɛntənsɪz] (IPA) 
Open sentences that are otherwise known as open propositions or open formulas are statements in mathematics and logic which contain a variable or unknown entity. The variable in an open sentence can be replaced by a number to produce a true or false statement. The term open sentence has several synonyms, including an open statement, an open formula, and an open predicate. Other terms used to describe an open sentence include an incomplete expression or an ambiguous expression. Open sentences can be complex and can consist of several variables and mathematical notations, but they are used to express relationships between various mathematical quantities.
