Chapter 2.1, Problem 2CYU

Explanation of Solution

Three operations used to build complex regular expressions from simpler regular expressions:

• Concatenation
  • The term concatenate means combining a string in a series without any spaces.
  • The “$o$” is the concatenation symbol. It provides a way to construct larger strings from smaller strings.
  • With the use of empty string, represented as “ϵ” the strings are concatenated. The empty string serves as both a left and right idempotent for concatenation.
• Alternation
  • Small finite sets are conveniently denoted by listing their elements