Dalmau, V. and Krokhin, A. and Larose, B. (2007) 'First-order definable retraction problems for posets and reflexive graphs.', Journal of logic and computation., 17 (1). pp. 31-51.
Abstract
A retraction from a structure P to its substructure Q is a homomorphism from P onto Q that is the identity on Q. We present an algebraic condition which completely characterzies all posets and all reflexive graphs Q such that the class of all posets or reflexive graphs, respectively, that admit a retraction onto Q is first-order definable.
| Item Type: | Article |
|---|---|
| Keywords: | Retraction, Homomorphism, Graphs, Posets, First-order definability. |
| Full text: | (AM) Accepted Manuscript Download PDF (167Kb) |
| Status: | Peer-reviewed |
| Publisher Web site: | http://dx.doi.org/10.1093/logcom/exl014 |
| Publisher statement: | This is a pre-copy-editing author-produced PDF of an article accepted for publication in Journal of logic and computation following peer review. The definitive publisher-authenticated version Dalmau, V. and Krokhin, A. and Larose, B. (2007) 'First-order definable retraction problems for posets and reflexive graphs.', Journal of logic and computation., 17 (1). pp. 31-51 is available online at: http://logcom.oxfordjournals.org/cgi/content/abstract/17/1/31 |
| Date accepted: | No date available |
| Date deposited: | 07 April 2010 |
| Date of first online publication: | February 2007 |
| Date first made open access: | No date available |
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