Module 4 Worksheet In Class Questions 1) (S4) Decision sorting: Input: list of integers Yes/ No Question: is the list in nondecreasing order? For the decision sorting problem, specify the following sets Universe of legal input instances: Set of yes input instances: Set of no input instances: 2) (S7) Specify the language recognition problem for L = the set of even length strings over {a,b} using both formats (traditional, 3 sets). Input: Yes/No question: Universe of legal input instances: Set of yes input instances: Set of no input instances: 3) (S9) Define an encoding scheme E for converting the following problem into a language recognition problem over alphabet {a}. Input: Non-negative integer n Yes/No question: Is n a prime number? What would E(4) be under your scheme? What is the resulting language L? 4) (S22) Which is true? a) A problem is solvable implies the problem is half-solvable. b) A problem is half-solvable implies the problem is solvable. Take home review questions 1) What is the type of an input instance in a language recognition problem? 2) Give both formulations (Input & Y/N question, 3 sets) of the LRP corresponding to the language L = the set of strings beginning with aaa over {a,b}. 3) What are Y(P), N(P), C(P), and I(P) for the following program? bool main(string x) { if ((x.length( ) % 2) = = 0) return (yes); else return(no); } Y(P) = N(P) = C(P) = I(P) = 4) For any program P that takes as input a string, can P ever solve a language other than Y(P)?