#### Filter Results:

- Full text PDF available (10)

#### Publication Year

2007

2011

- This year (0)
- Last 5 years (0)
- Last 10 years (10)

#### Publication Type

#### Co-author

#### Journals and Conferences

#### Key Phrases

Learn More

- Martin Grohe, Berit Grußien, André Hernich, Bastian Laubner
- Logical Methods in Computer Science
- 2011

We extend first-order logic with counting by a new operator that allows it to formalise a limited form of recursion which can be evaluated in logarithmic space. The resulting logic LREC has a data complexity in LOGSPACE, and it defines LOGSPACE-complete problems like deterministic reachability and Boolean formula evaluation. We prove that LREC is strictly… (More)

- Anuj Dawar, Martin Grohe, Bjarki Holm, Bastian Laubner
- 2009 24th Annual IEEE Symposium on Logic In…
- 2009

We introduce extensions of first-order logic (FO) and fixed-point logic (FP) with operators that compute the rank of a definable matrix. These operators are generalizations of the counting operations in FP+C (i.e. fixed-point logic with counting) that allow us to count the dimension of a definable vector space, rather than just count the cardinality of a… (More)

- Johannes Köbler, Sebastian Kuhnert, Bastian Laubner, Oleg Verbitsky
- SIAM J. Comput.
- 2011

We present a logspace algorithm for computing a canonical labeling, in fact a canonical interval representation, for interval graphs. To achieve this, we compute canonical interval representations of interval hypergraphs. This approach also yields a canonical labeling of convex graphs. As a consequence, the isomorphism and automorphism problems for these… (More)

- Bastian Laubner
- 2010 25th Annual IEEE Symposium on Logic in…
- 2010

We prove a characterization of all polynomialtime computable queries on the class of interval graphs by sentences of fixed-point logic with counting. More precisely, it is shown that on the class of unordered interval graphs, any query is polynomial-time computable if and only if it is definable in fixed-point logic with counting. This result is one of the… (More)

- Bastian Laubner
- 2011

Descriptive complexity theory is the area of theoretical computer science that is concerned with the abstract characterization of computations by means of mathematical logics. It shares the approach of complexity theory to classify problems on the basis of the resources that are needed to solve them. Instead of computational resources, however, descriptive… (More)

We present a logspace algorithm for computing a canonical interval representation and a canonical labeling of interval graphs. As a consequence, the isomorphism and automorphism problems for interval graphs are solvable in logspace.

We give a combinatorial classification of postsingularly finite exponential maps in terms of external addresses starting with the entry 0. This is an extension of the classification results for critically preperiodic polynomials [BFH] to exponential maps. Our proof relies on the topological characterization of postsingularly finite exponential maps given… (More)

We give a combinatorial classification of postsingularly finite exponential maps in terms of external addresses starting with the entry 0. This is an extension of the classification results for critically preperiodic polynomials [BFH] to exponential maps. Our proof relies on the topological characterization of postsingularly finite exponential maps given… (More)

We give a combinatorial classification of postsingularly finite exponential maps in terms of external addresses starting with the entry 0. This is an extension of the classification results for critically preperiodic polynomials [BFH] to exponential maps. Our proof relies on the topological characterization of postsingularly finite exponential maps given… (More)

- ‹
- 1
- ›