A form of notation, invented by the Polish mathematician Jan Lukasiewicz, in which each operator precedes its operands, e.g.
a + b is expressed as +ab
If all operators take exactly two operands, or if each operator has a specific number of operands, then no brackets are required since the order of evaluation is always uniquely defined; the notation can then be described as parenthesis-free. See also reverse Polish notation.
Subjects: Philosophy — Computing.