1. Let Σ be an alphabet. Prove or disprove that for every language L over alphabet Σ, if L2 = L, then L+ = L.

(For thought) a. A token of a computer language is any sequence of characters, with no intervening characters or white space, that taken as a unit has a unique meaning. Using this definition of a token, determine whether escape sequences, function names, and the keywords listed in Table 2.1 are tokens of the C++ language. b. Discuss whether adding white space to a message alters the message and whether messages can be considered tokens of C++. c. Using the definition of a token in Exercise 4a, determine whether the following statement is true: “Except for tokens of the language, C++ ignores all white space.”