```
CS 3350, Spring 2017, Test 1: typical mistakes

Problem 1-2:

* Next time, as I suggested during a preview, please construct a
non-deterministic automaton step by step, and show all the steps,
as we do in class. If all I see is a wrong non-deterministic
automaton, then all I know is that something is wrong. If I see it
step by step, it may be that you do not know the algorithm, but
made a minor mistake in one of the steps -- so you will get a lot
of partial credit.

* In a deterministic automaton, for each state and for each
symbol, there should be an arrow indicating what to do if in this
particular state, we see this particular symbol.

* Concatenation AB of two strings or of two languages is NOT
commutative: as I mentioned during the preview, if A is "John" and
B is "Smith", then AB is "JohnSmith" but BA is "mithJohn", these
are two different strings.

* Mistakes in the algorithm: mistakes in union, concatenation, and
Kleene star

Problem 3-4: do not confuse empty string /\ and empty set, they
are different.

Problem 5: for each state of the new automaton and for every
symbol, there should be an arrow indicating what to do if in this
particular state, we see this particular symbol.