Introduction to Logic

Exercise 9.1 - Syntax

Say whether each of the following expressions is a syntactically legal sentence of Herbrand Logic. Assume that a and b are object constants, f is a unary function constant, and p is a unary relation constant.

a. p(a)
b. p(f(a))
c. f(f(a))
d. p(f(f(a)))
e. p(f(p(a)))