Monadic predicate calculus

In logic, the monadic predicate calculus (also called monadic first-order logic) is the fragment of first-order logic in which all relation symbols in the signature are monadic (that is, they take only one argument), and there are no function symbols. All atomic formulas are thus of the form P ( x ) {displaystyle P(x)} , where P {displaystyle P} is a relation symbol and x {displaystyle x} is a variable. In logic, the monadic predicate calculus (also called monadic first-order logic) is the fragment of first-order logic in which all relation symbols in the signature are monadic (that is, they take only one argument), and there are no function symbols. All atomic formulas are thus of the form P ( x ) {displaystyle P(x)} , where P {displaystyle P} is a relation symbol and x {displaystyle x} is a variable.