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MFCS
2005
Springer
14 years 8 days ago
Explicit Inapproximability Bounds for the Shortest Superstring Problem
Abstract. Given a set of strings S = {s1, . . . , sn}, the Shortest Superstring problem asks for the shortest string s which contains each si as a substring. We consider two measur...
Virginia Vassilevska
MFCS
2005
Springer
14 years 8 days ago
On Small Hard Leaf Languages
This paper deals with balanced leaf language complexity classes, introduced independently in [1] and [14]. We propose the seed concept for leaf languages, which allows us to give ā...
Falk Unger
MFCS
2005
Springer
14 years 8 days ago
The Generalization of Dirac's Theorem for Hypergraphs
Endre Szemerédi, Andrzej Rucinski, Vojtech ...
MFCS
2005
Springer
14 years 8 days ago
D-Width: A More Natural Measure for Directed Tree Width
Due to extensive research on tree-width for undirected graphs and due to its many applications in various ļ¬elds it has been a natural desire for many years to generalize the idea...
Mohammad Ali Safari
MFCS
2005
Springer
14 years 8 days ago
On Beta-Shifts Having Arithmetical Languages
Let Ī² be a real number with 1 < Ī² < 2. We prove that the language of the Ī²-shift is āˆ†0 n iļ¬€ Ī² is a āˆ†n-real. The special case where n is 1 is the independently inter...
Jakob Grue Simonsen
MFCS
2005
Springer
14 years 8 days ago
Strict Language Inequalities and Their Decision Problems
Systems of language equations of the form {Ļ•(X1, . . . , Xn) = āˆ…, Ļˆ(X1, . . . , Xn) = āˆ…} are studied, where Ļ•, Ļˆ may contain set-theoretic operations and concatenation; the...
Alexander Okhotin
MFCS
2005
Springer
14 years 8 days ago
Concurrent Automata vs. Asynchronous Systems
We compare the expressive power of two automata-based ļ¬nite-state models of concurrency. We show that Drosteā€™s and Kuskeā€™s coherent stably concurrent automata and Bednarczykā...
Rémi Morin
MFCS
2005
Springer
14 years 8 days ago
Inverse Monoids: Decidability and Complexity of Algebraic Questions
This paper investigates the word problem for inverse monoids generated by a set Ī“ subject to relations of the form e = f, where e and f are both idempotents in the free inverse m...
Markus Lohrey, Nicole Ondrusch
MFCS
2005
Springer
14 years 8 days ago
Dimension Is Compression
Abstract. Eļ¬€ective fractal dimension was deļ¬ned by Lutz (2003) in order to quantitatively analyze the structure of complexity classes. Interesting connections of eļ¬€ective dim...
María López-Valdés, Elvira Ma...