(ix) A

nondeterministic automaton can have more than one possible path for an input sequence.

An assertion graph with n states resulted in a nondeterministic automaton with 3 x n states.

Complementing a nondeterministic automaton with n states resulted in an automaton with [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] [23].

To clarify how nondeterministic models work, mainly their acceptance mechanism, the CM unit uses the magic coin metaphor, introduced by Harel (1987): Students are told that they should think of a nondeterministic automaton as if it were equipped with a coin which it flips before it decides which transition to choose.

It should be emphasized that we did not ask the students specifically to construct a nondeterministic automaton, so they had the freedom of choice.

For one sublanguage, he designed a basically nondeterministic automaton, with a redundant self loop with b in [q.sub.1] (Figure 18).

An alternative and very useful way to consider the problem is to model the search with a nondeterministic automaton (NFA).

There are two main trends: parallelize the work of the nondeterministic automaton that solves the problem (Figure 15), or parallelize the work of the dynamic programming matrix.

Notice that if we convert the nondeterministic automaton to a deterministic one with O(n) search time, we get an improved version of the KMP algorithm [Knuth et al.

We can represent the transition relation [Delta] of a

nondeterministic automaton on binary trees using [[Beta].sup.+]({0, 1} x Q).

Note that a nondeterministic automaton can have many runs on w.

Note that many nodes of [T.sub.r] can correspond to the same node of T; in contrast, in a run of a nondeterministic automaton on <T, V> there is a one-to-one correspondence between the nodes of the run and the nodes of the input tree.