Weizmann Logo
Electronic Colloquium on Computational Complexity

Under the auspices of the Computational Complexity Foundation (CCF)

Login | Register | Classic Style

All reports by Author Frank Stephan:

TR04-058 | 28th May 2004
John Case, Sanjay Jain, Eric Martin, Arun Sharma, Frank Stephan

Identifying Clusters from Positive Data

The present work studies clustering from an abstract point of view
and investigates its properties in the framework of inductive inference.
Any class $S$ considered is given by a numbering
$A_0,A_1,...$ of nonempty subsets of the natural numbers
or the rational k-dimensional vector space as a hypothesis space.
A clustering ... more >>>

TR04-038 | 27th April 2004
John Case, Sanjay Jain, Rüdiger Reischuk, Frank Stephan, Thomas Zeugmann

A Polynomial Time Learner for a Subclass of Regular Patterns

Presented is an algorithm (for learning a subclass of erasing regular
pattern languages) which
can be made to run with arbitrarily high probability of
success on extended regular languages generated by patterns
$\pi$ of the form $x_0 \alpha_1 x_1 ... \alpha_m x_m$
for unknown $m$ but known $c$,
more >>>

TR04-015 | 24th February 2004
Richard Beigel, Harry Buhrman, Peter Fejer, Lance Fortnow, Piotr Grabowski, Luc Longpré, Andrej Muchnik, Frank Stephan, Leen Torenvliet

Enumerations of the Kolmogorov Function

A recursive enumerator for a function $h$ is an algorithm $f$ which
enumerates for an input $x$ finitely many elements including $h(x)$.
$f$ is an $k(n)$-enumerator if for every input $x$ of length $n$, $h(x)$
is among the first $k(n)$ elements enumerated by $f$.
If there is a $k(n)$-enumerator for ... more >>>

TR97-013 | 13th February 1997
Bernd Borchert, Dietrich Kuske, Frank Stephan

On Existentially First-Order Definable Languages and their Relation to NP

Pin & Weil [PW95] characterized the automata of existentially
first-order definable languages. We will use this result for the following
characterization of the complexity class NP. Assume that the
Polynomial-Time Hierarchy does not collapse. Then a regular language
L characterizes NP as an unbalanced polynomial-time leaf language
if and ... more >>>

TR96-060 | 19th November 1996
Bernd Borchert, Frank Stephan

Looking for an Analogue of Rice's Theorem in Complexity Theory

Rice's Theorem says that every nontrivial semantic property
of programs is undecidable. It this spirit we show the following:
Every nontrivial absolute (gap, relative) counting property of circuits
is UP-hard with respect to polynomial-time Turing reductions.

more >>>

TR96-033 | 6th March 1996
Bernd Borchert, Desh Ranjan, Frank Stephan

On the Computational Complexity of some Classical Equivalence Relations on Boolean Functions

The paper analyzes in terms of polynomial time many-one reductions
the computational complexity of several natural equivalence
relations on Boolean functions which derive from replacing
variables by expressions. Most of these computational problems
turn out to be between co-NP and Sigma^p_2.

more >>>

ISSN 1433-8092 | Imprint