The regular expression for this language is \((a + b)*\) .
The context-free grammar for this language is: elements of the theory of computation solutions
We can design a pushdown automaton with two states, q0 and q1. The automaton starts in state q0 and pushes the symbols of the input string onto the stack. When it reads a c, it moves to state q1 and pops the symbols from the stack. The automaton accepts a string if the stack is empty when it reaches the end of the string. The regular expression for this language is \((a + b)*\)
We can design a Turing machine with three states, q0, q1, and q2. The machine starts in state q0 and moves to state q1 when it reads the first symbol of the input string. It then moves to state q2 and checks if the second half of the string is equal to the first half. The machine accepts a string if it is in state q2 and has checked all symbols. When it reads a c, it moves to
Turing machines are the most powerful type of automata. They have a tape that can be read and written, and they can move left or right on the tape. Turing machines can be used to recognize recursively enumerable languages, which are languages that can be described using Turing machines.