NOTE - On the Membership Problem for the Elementary Closure of a Polyhedron

COMBINATORICA ◽  
1999 ◽  
Vol 19 (2) ◽  
pp. 297-300 ◽  
Author(s):  
Friedrich Eisenbrand
Keyword(s):  
Membership Problem ◽  
Elementary Closure

WHEN CHURCH-ROSSER BECOMES CONTEXT FREE

2007 ◽  
Vol 18 (06) ◽  
pp. 1293-1302 ◽  
Author(s):  
MARTIN KUTRIB ◽  
ANDREAS MALCHER
Keyword(s):  
Linear Time ◽  
Membership Problem ◽  
Closure Properties ◽  
Context Free Language ◽  
Arithmetic Hierarchy ◽  
Context Free ◽  
Free Language

We investigate the intersection of Church-Rosser languages and (strongly) context-free languages. The intersection is still a proper superset of the deterministic context-free languages as well as of their reversals, while its membership problem is solvable in linear time. For the problem whether a given Church-Rosser or context-free language belongs to the intersection we show completeness for the second level of the arithmetic hierarchy. The equivalence of Church-Rosser and context-free languages is Π1-complete. It is proved that all considered intersections are pairwise incomparable. Finally, closure properties under several operations are investigated.

scholarly journals On the computational algorithm related to antikeys

2016 ◽  
Vol 14 (2) ◽  
pp. 1-7
Author(s):  
Vũ Đức Thi
Keyword(s):  
Time Complexity ◽  
Computational Algorithm ◽  
Functional Dependency ◽  
Membership Problem ◽  
Closed Set ◽  
Dependency Relation ◽  
Key Word ◽  
Relation Scheme

The keys and antikeys play important roles for the investigation of functional dependency in the relational datamodel. The main purpose of this paper is to prove that the time complexity of finding a set of antileys for a given relation scheme S is exponential in the number of attributes. Some another results connecting the functional dependency are given. Key Word and phrase: Relation, relational datamodel, functionsl dependency, relation scheme, generating Armstrong relation, dependency inference, strong schemen, membership problem, closure, closed set, minimal generater, key, minimal key, antikey.

Membership Problem for Two-Dimensional General Row Jumping Finite Automata

2020 ◽  
Vol 31 (04) ◽  
pp. 527-538
Author(s):  
Grzegorz Madejski ◽  
Andrzej Szepietowski
Keyword(s):  
Computational Model ◽  
Turing Machine ◽  
Finite Automaton ◽  
Finite Automata ◽  
The Other ◽  
Membership Problem ◽  
Two Dimensional ◽  
Np Complete ◽  
Nondeterministic Turing Machine ◽  
Membership Problems

Two-dimensional general row jumping finite automata were recently introduced as an interesting computational model for accepting two-dimensional languages. These automata are nondeterministic. They guess an order in which rows of the input array are read and they jump to the next row only after reading all symbols in the previous row. In each row, they choose, also nondeterministically, an order in which segments of the row are read. In this paper, we study the membership problem for these automata. We show that each general row jumping finite automaton can be simulated by a nondeterministic Turing machine with space bounded by the logarithm. This means that the fixed membership problems for such automata are in NL, and so in P. On the other hand, we show that the uniform membership problem is NP-complete.

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