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One-stack automata as acceptors of context-free languages

This paper presents one-stack automata as acceptors of context-free languages; these are equivalent to Pushdown Automata which are well known in automata theory. As equivalence relations such as equivalence of Turing Machines and two-stack Pushdown Automata help in learning general properties of formal modeling, the equivalence relation of Pushdown Automata and one-stack automata also helps in learning general properties of context-free language modeling. One-stack automata are helpful to students for several reasons including: (1) their contrast with two-stack Pushdown Automata and multi-stack automata is revealing for computability; (2) their computer animation is helpful for learning their salient features; (3) their graphical representation is more easily obtained by augmenting Non-Deterministic Finite Automata for regular languages which usually precede context-free language acceptors in the logical sequence of ideas.