Polish notation (
PN), also known as
normal Polish notation (
NPN),
Lukasiewicz notation,
Warsaw notation,
Polish prefix notation or simply
prefix notation, is a form of notation for
logic,
arithmetic, and
algebra. Its distinguishing feature is that it places
operators to the left of their
operands. If the
arity of the operators is fixed, the result is a syntax lacking parentheses or other brackets that can still be parsed without ambiguity. The
Polish logician
Jan Lukasiewicz invented this notation in 1924 in order to simplify
sentential logic.