Consider the augmented grammar G is:
S` -> S S -> a S -> (T) T -> T,S T -> S
I have tried to construct parse table. But, when I read '(' nonterminal Symbol (item 3), there is no action table elements either 'shift' or 'reduce'.
I3: S -> (.T) T -> .T,S T -> .S
so I can't construe '(a,(a,a))' in this Parse table. then is it ambiguous grammar? or I wrong the answer?