Turing Kernelization for Finding Long Paths in Graph Classes Excluding a Topological Minor
The notion of Turing kernelization investigates whether a polynomial-time algorithm can solve an NP-hard problem, when it is aided by an oracle that can be queried for the answers to bounded-size subproblems. One of the main open problems in this direction is whether k - Path admits a polynomial Tur...
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| Published in: | Algorithmica Vol. 81; no. 10; pp. 3936 - 3967 |
|---|---|
| Main Authors: | , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
New York
Springer US
01.10.2019
Springer Nature B.V |
| Subjects: | |
| ISSN: | 0178-4617, 1432-0541 |
| Online Access: | Get full text |
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| Summary: | The notion of Turing kernelization investigates whether a polynomial-time algorithm can solve an NP-hard problem, when it is aided by an oracle that can be queried for the answers to bounded-size subproblems. One of the main open problems in this direction is whether
k
-
Path
admits a polynomial Turing kernel: can a polynomial-time algorithm determine whether an undirected graph has a simple path of length
k
, using an oracle that answers queries of size
k
O
(
1
)
? We show this can be done when the input graph avoids a fixed graph
H
as a topological minor, thereby significantly generalizing an earlier result for bounded-degree and
K
3
,
t
-minor-free graphs. Moreover, we show that
k
-
Path
even admits a polynomial Turing kernel when the input graph is not
H
-topological-minor-free itself, but contains a known vertex modulator of size bounded polynomially in the parameter, whose deletion makes it so. To obtain our results, we build on the graph minors decomposition to show that any
H
-topological-minor-free graph that does not contain a
k
-path, has a separation that can safely be reduced after communication with the oracle. |
|---|---|
| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 |
| ISSN: | 0178-4617 1432-0541 |
| DOI: | 10.1007/s00453-019-00614-4 |