• A, … , F, S : nonterminals
• S : the start nonterminal
• a, … , d : terminals
• U, … , Z : members
of (N È T)
• u, … , z : members
of (N È T)*
• p : sequence of productions
A subset of rules of the form:
A
® x1, A ® x2 , …, A ® xn
can be simply written as:
A
® x1 | x2 | … | xn