Prove that the following grammar is ambiguous

Question

S-> A|B|AB

A-> aA, B-> bB, A->€, B->€

€ is the empty string.

Find a string and show that it has two

a-) parse trees b-) leftmost derivations c-) rightmost derivations

How many empty strings (€) do you pay? – Daniel Daranas Apr 10 '14 at 09:37 — Daniel Daranas, Apr 10 '14 at 09:37
That is just a symbol € not a money symbol :) – Tihyros Apr 10 '14 at 09:41 — Tihyros, Apr 10 '14 at 09:41

score 1 · Accepted Answer · answered Apr 10 '14 at 09:41

1

We're not gonna do your homework.

Build the parse tree using leftmost and rightmost derivations. If you can find any ambiguity, it is ambigious.

S-> A|B|AB is the key part. Try using both A, B and AB.

answered Apr 10 '14 at 09:41

Filip Haglund

That is a sample of midterm question ı try to learn how to solve this question.. – Tihyros Apr 10 '14 at 09:44
Well, there are three ways to parse the empty string, A->€, B->€ and AB -> €€ -> € – Filip Haglund Apr 10 '14 at 10:46
if you're happy with it as an answer, please mark it as the accepted answer – Filip Haglund Apr 12 '14 at 00:39

1 Answers1