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Neural Networks and Computational Learning Theory

 

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NeuroCOLT Technical Report NC-TR-94-007

 

On the power of real Turing machines over binary inputs

Felipe Cucker,
Universitat Pompeu Fabra,
Balmes 132, Barcelona 08008, SPAIN
&
Dima Grigoriev,
Depts. of Comp. Science and Maths,
Penn State University,
University Park, PA 16802, USA

Abstract
In recent years the study of the complexity of computational problems involving real numbers has been an increasing research area. Blum, Shub and Smale (1989) proposed a computational model ---the real Turing machine--- for dealing with the above problems was developed.  The aim of this paper is to prove that $\BP(\PAR)=\;$PSPACE/{\it poly} where $\PAR$ is the class of sets computed in parallel polynomial time by (ordinary) real Turing machines.  As a consequence we obtain the existence of binary sets that do not belong to the Boolean part of $\PAR$ (an extension of the result of Koiran (1994) since $\PH\subseteq\PAR$) and a separation of complexity classes in the real setting.

 

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