• For all questions that ask you to build an NFA, please make sure there is non-determinism somewhere in the machine. In other words, don't provide a DFA as an answer. Also, you cannot use o- transitions unless I have explicitly specified o-NFA for the question.
• For all questions that ask you to build an o-NFA, please make sure there is at least one explicit o transition somewhere - i.e., don't provide a regular NFA without any o-transition or DFA as an answer.
• For NFA or o-NFA questions, try to take advantage of non-determinism in the interest of keeping the design simple and elegant.
1. Build NFAs for the following two languages.
a) The set of strings over alphabet {a, b, c} such that the last symbol in the string has appeared before.
b) The set of strings over alphabet {a, b, c} such that the last symbol in the string has not appeared before.
You can assume that neither of these two languages contain o in them.