Papyrus 95

Template:Multiple issues In computer science, a counter automaton is a Pushdown automaton with only two symbols, A and the initial symbol in $\mathrm{\Gamma }$ (the finite set of stack symbols). This class of automata can recognize a subset of Context free languages, for instance the language:

$\{a^n{b}^n:n\in \mathbb{\mathbb{N}}\}$

To accept the above language, let x be a word on the form above. The automaton can use the symbol A to count the number of a's in x (writing an A for each a in x) and deleting an A for each b in x.

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