A hierarchy that does not collapse : alternations in low level space
A new algorithm for recognizing the unknot.
A new decidable Horn fragment of predicate calculus.
A non-deteministic time hierarchy over the reals.
A note on separating the relativized polynomial time hierarchy by immune sets
A note on the asymptotic and computational complexity of graph distinguishability.
A survey on real structural complexity theory.
Algebraic complexity theory. I: An introduction. (Algebraische Komplexitätstheorie. I: Eine Einführung.)
Algebraic complexity theory. II: Tast matrix multiplication and combinatorics. (Algebraische Komplexitätstheorie. II: Schnelle Matrixmultiplikation und Kombinatorik.)
Algebraic complexity theory. III: On the complexity of the computation of permanents. (Algebraische Komplexitätstheorie. III: Zur Berechnungskomplexität von Permanenten.)
Autour de nouvelles notions pour l’analyse des algorithmes d’approximation : formalisme unifié et classes d’approximation
The main objective of the polynomial approximation is the development of polynomial time algorithms for NP-hard problems, these algorithms guaranteeing feasible solutions lying “as near as possible” to the optimal ones. This work is the fist part of a couple of papers where we introduce the key-concepts of the polynomial approximation and present the main lines of a new formalism. Our purposes are, on the one hand, to present this theory and its objectives and, on the other hand, to discuss the...
Autour de nouvelles notions pour l’analyse des algorithmes d’approximation : de la structure de NPO à la structure des instances
Cet article est la suite de l’article «Autour de nouvelles notions pour l’analyse des algorithmes d’approximation : formalisme unifié et classes d’approximation» où nous avons présenté et discuté, dans le cadre d’un nouveau formalisme pour l’approximation polynomiale (algorithmique polynomiale à garanties de performances pour des problèmes NP-difficiles), des outils permettant d’évaluer, dans l’absolu, les proporiétés d’approximation de problèmes difficiles. Afin de répondre pleinement à l’objectif...
Autour de nouvelles notions pour l'analyse des algorithmes d'approximation : de la structure de NPO à la structure des instances
This paper is the continuation of the paper “Autour de nouvelles notions pour l'analyse des algorithmes d'approximation: Formalisme unifié et classes d'approximation” where a new formalism for polynomial approximation and its basic tools allowing an “absolute” (individual) evaluation the approximability properties of NP-hard problems have been presented and discussed. In order to be used for exhibiting a structure for the class NPO (the optimization problems of NP), these tools must be enriched...
Autour de nouvelles notions pour l'analyse des algorithmes d'approximation : formalisme unifié et classes d'approximation
Cet article est le premier d'une série de deux articles où nous présentons les principales caractéristiques d'un nouveau formalisme pour l'approximation polynomiale (algorithmique polynomiale à garanties de performances pour les problèmes NP-difficiles). Ce travail est l'occasion d'un regard critique sur ce domaine et de discussions sur la pertinence des notions usuelles. Il est aussi l'occasion de se familiariser avec l'approximation polynomiale, de comprendre ses enjeux et ses méthodes. Ces deux...
Bijective sequential mappings of a free monoid onto another
Bounded queries to arbitrary sets
Communication complexity and lower bounds on multilective computations
Communication Complexity and Lower Bounds on Multilective Computations
Communication complexity of two-party (multiparty) protocols has established itself as a successful method for proving lower bounds on the complexity of concrete problems for numerous computing models. While the relations between communication complexity and oblivious, semilective computations are usually transparent and the main difficulty is reduced to proving nontrivial lower bounds on the communication complexity of given computing problems, the situation essentially changes, if one...
Complexity classes between and
Complexity classes for membrane systems
We compare various computational complexity classes defined within the framework of membrane systems, a distributed parallel computing device which is inspired from the functioning of the cell, with usual computational complexity classes for Turing machines. In particular, we focus our attention on the comparison among complexity classes for membrane systems with active membranes (where new membranes can be created by division of existing membranes) and the classes PSPACE, EXP, and EXPSPACE.