Showing papers on "Pushdown automaton published in 1981"
25 citations
TL;DR: In this paper, it was shown that for each inside-out (or IO-) macro language $L, there is a λ-free grammar with the following property: for each $x$ in $L, there is derivation of length at most linear in the length of $x.
Abstract: Starting from Fischer's IO Standard Form Theorem we show that for each inside-out (or IO-) macro language $L$, there is a $\lambda$-free IO-macro grammar with the following property: for each $x$ in $L$, there is a derivation of $x$ of length at most linear in the length of $x$. Then we construct a nondeterministic log-space bounded auxiliary pushdown automaton which accepts $L$ in polynomial time. Therefore the IO-macro languages are (many-one) log-space reducible to the context-free languages. Consequently, the membership problem for IO-macro languages can be solved deterministically in polynomial time and in space $(\log n)^2$.
20 citations
17 citations
TL;DR: New results concerning the space complexity of languages accepted by stack automata, alternating stack Automata, and alternating pushdown automata are derived.
Abstract: New results concerning the space complexity of languages accepted by stack automata, alternating stack automata, and alternating pushdown automata are derived. Some of the results generalize previously known results.
15 citations
11 May 1981
TL;DR: It is shown that the monadic second-order theory of any context-free graph is decidable, and using the results obtained and Rabin's theorem, this work shows that cellular automata and vector addition systems make sense on a very general class of graphs.
Abstract: We have discovered a very strong connection between certain areas of theoretical computer science—the theory of context-free languages and pushdown automata, tiling problems, cellular automata, and vector addition systems—and certain concepts from group theory, topology, and second-order logic. We use these concepts to investigate a rather wide class of graphs which we call context-free graphs. Using the results obtained and Rabin's theorem that the monadic second-order theory of the infinite binary tree is decidable, we are able to show that the monadic second-order theory of any context-free graph is decidable. Cellular automata and vector addition systems are usually considered as involving the grid of integer lattice points in n-dimensional space. We show that such systems make sense on a very general class of graphs and, in contrast to the classical case, all the relevant algorithmic problems concerning such systems are solvable on context-free graphs.
11 citations
TL;DR: It is shown that there exists a deterministic array-bounded PDA which can traverse any simply connected pattern and halt when the traversal is complete.
10 citations
TL;DR: The transformation is proved to be the best possible one in the following sense: for each choice of the parametersn0 + 1 stack symbols for any desired value realtime PDAM0 such that any equivalent PDAM (whether realtime or not) havingn states must have at least ⌈(n0/n)2 p0⌉ stack symbols.
Abstract: A transformation is presented which converts any pushdown automaton (PDA)M
0 withn
0 states andp
0 stack symbols into an equivalent PDAM withn states and ⌈n
0
/n⌉2
p
0 stack symbols into an equivalent ofn, 1⩽n
10 citations
TL;DR: It is shown that the B-fuzzy pushdown automata can accept context sensitive languages by setting a threshold, while the ( fuzzy) pushdown automation can accept only context-free languages.
Abstract: FUZZY phushdown automata and B-fuzzy pushdown automata are defined as an extension of pushdown automata. It is shown that the B-fuzzy pushdown automata can accept context sensitive languages by setting a threshold, while the (fuzzy) pushdown automata can accept only context-free languages.
8 citations
11 May 1981
TL;DR: Since L is accepted by a two-way deterministic pushdown automaton, it is consequently shown that one pushdown stack is more powerful than one counter for deterministic two- way machines.
Abstract: We define a language L and show that is cannot be recognized by any two way deterministic counter machine. It is done by fooling any given such machine; i.e. showing that if it accepts L' ⊇ L, then L'-L ≠ φ. For this purpose, an argument stronger than the well known crossing sequence argument needs to be introduced. Since L is accepted by a two-way deterministic pushdown automaton, we consequently show that one pushdown stack is more powerful than one counter for deterministic two-way machines.
7 citations
TL;DR: On purpose to reduce the size of this array, the compressed configurations are introduced which will record terminators of configurati.ons and use recorded values to speed up +he automaton.
TL;DR: It is shown that if T(n) is the time to recognize context-free languages then theTime to recognjze languages from NPDA(k) is O(T(nk), which is less than O(n3k) time.
TL;DR: The purpose is to place exactly the automaton in a pre-specified final state from an unknown initial state, in using stochastic information on state-classes using a Bayesian decision strategy.