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On Preservation under Homomorphisms and Unions of Conjunctive Queries

Summary: Shows that first-order formulas preserved under homomorphisms on finite structures are equivalent to existential-positive (i.e., unions of conjunctive) formulas for many natural classes. Specifically proves the finite homomorphism-preservation theorem for classes of bounded degree, bounded treewidth, and more generally classes whose cores exclude some minor. (summarized by gpt-5-mini on Feb 09 2026)

Paper ID
1334
Venue
PODS
Year
2004
Pagerank
6.2156238e-05
Overall Rank
4,405 | 69.36%
DOI
-

Incoming Non-self Citations Over Time

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Incoming Citations (Sorted by Pagerank)

Showing 5 of 5 citing papers.

Rank Citing Paper Year Venue Pagerank
2,562 Explaining Missing Answers to SPJUA Queries 2010 VLDB 8.5386194e-05
5,494 Incomplete Data: What Went Wrong, and How to Fix It 2014 PODS 5.4759469e-05
6,858 When is Naive Evaluation Possible? 2013 PODS 4.9060157e-05
10,343 Circuit Bounds for Conjunctive Queries with Self-joins 2025 PODS 4.1945683e-05
11,333 LACE: A Logical Approach to Collective Entity Resolution 2022 PODS 4.1945683e-05
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Outgoing Citations (Sorted by Pagerank)

Showing 3 of 3 cited papers.

Citations counted here include only citations to other VLDB/SIGMOD/CIDR/PODS papers in this database.

Rank Cited Paper Year Venue Pagerank
407 Conjunctive-Query Containment and Constraint Satisfaction 1998 PODS 0.00024004562
494 Data Exchange: Getting to the Core 2003 PODS 0.00021805832
1,122 Bottom-Up Beats Top-Down For Datalog 1989 PODS 0.0001385042
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