"S 1.3 A palindrome can be defined as a string that reads the same forward and backward, or by the following definition. 1) e is a palindrome 2) If a is any symbol, then the string a is a palindrome. 3) If a is any symbol and x is a palindrome, then axa is a palindrome. 4) Nothing is a palindrome unless it follows from (1) through (3). Prove by induction that the two definitions are equivalent