INT201, Assignment 1
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INT201, Assignment 1
21-22/S1
Question 1
Let Σ = {a,b}. Define A = {w ∈ Σ* | | w |≥ 2, second-to-last symbol of w is a} (20 marks)
(a) List the first 4 strings in A in lexicographic order. (4 marks)
(b) Draw a DFA for A.(16 marks)
Question 2
Let E, F be regular expressions, and E = 0, F = 1. (20 marks) (a) Give a DFA that accepts E n F . (4 marks)
(b) Give a DFA that accepts EF . (4 marks)
(c) Give a DFA that accepts (E n F)EF . (6 marks)
(d) Give a DFA that accepts (EF)* . (6 marks)
Question 3
Convert the given NFA to its corresponding DFA. (20 marks)
Question 4
Design context free grammars for the following languages (only providing rules). (20 marks)
(a) The set {an | n ≥ 1} (6 marks)
(b) The set {0n 1n | n ≥ 1} (6 marks)
(c) The set {ai bj ci e2 | i,j ≥ 0} (8 marks)
Question 5
Let Σ = {a,b}, and consider the language A = {w ∈ Σ* | w has more b′ s than a′ s}. (20 marks)
(a) Describe pumping lemma for regular languages. (4 marks)
(b) Prove that A is not a regular language. (16 marks)
2023-01-06