DocumentCode :
1992607
Title :
Unambiguous polynomial hierarchies and exponential size
Author :
Lange, Klaus-Jörn ; Rossmanith, Peter
Author_Institution :
Fakultat fur Inf., Tech. Univ. Munchen, Germany
fYear :
1994
fDate :
28 Jun- 1 Jul 1994
Firstpage :
106
Lastpage :
115
Abstract :
The classes NCk and ACk are defined by computational devices of polynomial size, i.e. by devices using a polynomially bounded number of gates or processors. We consider the case of exponential size, which results in classes between P and PSPACE. In this way, we get new characterizations of P and UP. The resulting relations of nondeterminism, unambiguity, and determinism to several types of simultaneous write access to a shared memory perfectly resemble the polynomial case. A new phenomenon is the equivalence of concurrent read, exclusive read, and owner read for arbitrary types of write access in the case of exponential size. In the exponential case, circuits of bounded depth characterize the polynomial hierarchy. Using the notion of an unambiguous circuit, we give a uniform framework to relate the various types of unambiguous polynomial hierarchies and to explain their differences
Keywords :
computational complexity; polynomials; ACk; NCk; PSPACE; bounded depth circuits; computational devices; concurrent read; determinism; exclusive read; exponential size; logic gates; nondeterminism; owner read; polynomially bounded number; processors; shared memory; simultaneous write access; unambiguous circuit; unambiguous polynomial hierarchies; Automata; Circuits; Equations; Phase change random access memory; Polynomials; Turing machines; USA Councils;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Structure in Complexity Theory Conference, 1994., Proceedings of the Ninth Annual
Conference_Location :
Amsterdam
Print_ISBN :
0-8186-5670-0
Type :
conf
DOI :
10.1109/SCT.1994.315812
Filename :
315812
Link To Document :
بازگشت