Question

A bit string is a sequence of zero or more bits. The length of this string is the number of bits in the string.

Review the definition of bit string(see above). Give a recursive definition for the set of bit strings {0^r 1^s 0^r | r, s is element of Natural numbers}. Note the number of 0's must be equal, but the number of 1's may be different from the number of 0's.