Showing papers on "Pushdown automaton published in 1972"

Program Schemes with Pushdown Stores

Abstract: We attempt to characterize classes of schemes allowing pushdown stores, building on an earlier work by Constable and Gries [1]. We study the effect (on the computational power) of allowing one, two, or more pushdown stores, both with and without the ability to detect when a pds is empty. A main result is that using one pds is computationally equivalent to allowing recursive functions.We also study the effect of adding the ability to do integer arithmetic, and multidimensional arrays.

Some aspects of linear space automata

Abstract: Linear space automaton is introduced as a generalization of probabilistic automaton and its various properties are investigated Linear space automaton has the abilities equivalent to probabilistic automaton but we can treat the former more easily than the latter because we can make use of properties of the linear space, successfully First the solutions are given for the problems of connectivity, state equivalence, reduction and identification of linear space automata Second, the matrix representation of linear space automaton is investigated and the relations between linear space automaton and probabilistic automaton are shown Third, we discuss the closure properties of the family of all real functions on a free semigroup Σ* which are defined by linear space automata and then give a solution to the synthesis problem of linear space automata Finally, some considerations are given to the problems of sets of tapes accepted by la's and also of operations under which the family of all the output functions of la's is not closed

Select properties of the graph model of a general automaton

Abstract: Select properties are presented for a graph model of a general automaton consisting of a processor, environment and time graph. The properties, stated in the form of theorems and corollaries, deal with connectedness, number of points and lines and indegree and outdegree as the model relates to the automaton's sets, functions and characteristics. The properties are illustrated by an example automaton.

Relationship between Pushdown Automata and Tape-Bounded Turing Machines.

Abstract: Recall that to define a language we can either: 1. Give a set of rules (i.e. a grammar) to produce all the legal strings (sentences) of the language. 2. Provide a machine (i.e. an algorithm) to recognise all the sentences of the language. There is a close relationship between the two approaches. Commonly we define a language by giving a grammar and then base parsers (or compilers) on the corresponding machine. The machines are automata like Turing machines, but constrained in the same sense as the Chomsky hierarchy. Finite State Control input tape read head a0 a1 a2 ... Auxiliary Memory The input tape is a sequence of tokens. Each time a symbol is processed the read head advances. The auxiliary memory is usually a linear organisation (e.g. a stack). The memory alphabet is usually V t ∪V n. The finite state control can be in any one of a finite number of states. Each action of the machine may change the FSC state, change the auxiliary memory, advance to the next input symbol. The action of the machine depends on the current FSC state, the current input symbol, the current memory symbol(s). The machine starts in some particular start state (q 0), with the read head at the first input symbol (a 0), with the memory empty. A machine accepts an input string as a sentence of the language if it reaches a goal state with the input exhausted.

Infix to Prefix Translation: The Insufficiency of a Pushdown Stack

Abstract: The permutations of the input string achievable by an algorithm which uses a single pushdown stack and M random access storage locations are characterized, and the characterization is used to show that no such algorithm can translate arithmetic expressions from infix to prefix.

Behavior of G-Type Automata in a Matrix Game Against Automata with Linear Strategy

Abstract: Among the tremendous variety of environments (i.e., competitive situations) in which a G-type automaton can find itself (the definition of such an automaton and the basic notation was taken from Sragovich [1]), the following case is of special interest. Let M = ‖aij‖ be a numerical matrix with the dimension k × in, and let A be an automaton capable of m moves consisting of the selection of a number from a column of matrix M. In response to a move Yi, when i = 1, …,k, of a G-type automaton and of the j-th move of the A automaton, the former will be fed a number aij whereas the latter (which is defined by a certain rule) will be fed an element of its input alphabet. For the above G-type automaton, the matrix M and the automaton A are a switching environment.