CSCI 311/500 Models of Computation Homework 4 Due: Turn in hand-written or typed solution or upload your solution to blackboard as Homework 4 (no scans) by Friday, October 26th at 5pm. Instructions: Everyone should do problem 1. Undergraduates do any TWO of problems 2-4. Graduates must do all four problems 1. Show that if L is regular, then the language tail is also regular, where tail(L) = {y: zy E L for some z e *) 2. Use the pumping lemma to show that the following language is not regular: 3. Use the pumping lemma to show that the following language is not regular: 4. Use the pumping lemma to show that the folowing language is not regular