We investigate confluence of rewriting with Equational Generalized Term Rewriting Systems R, consisting of Horn clauses, some of them defining conditional equations s = t ⇐ c and rewriting rules 𝓁 → r ⇐ c. In both cases, c is a sequence of atoms, possibly defined by using additional Horn clauses. Such systems include Equational Term Rewriting Systems and (join, oriented, and semi-equational) Conditional Term Rewriting Systems. A set of equations E defines an equivalence =_E and quotient set T(F,X)/=_E of terms, where reductions s →_{R/E}t using rules in R occur. For such systems, we obtain a finite set of conditional pairs π, which can be viewed as logical sentences, to prove and disprove confluence of →_{R/E} by (dis)proving joinability of such conditional pairs π.
@InProceedings{lucas:LIPIcs.CSL.2024.37, author = {Lucas, Salvador}, title = {{Confluence of Conditional Rewriting Modulo}}, booktitle = {32nd EACSL Annual Conference on Computer Science Logic (CSL 2024)}, pages = {37:1--37:21}, series = {Leibniz International Proceedings in Informatics (LIPIcs)}, ISBN = {978-3-95977-310-2}, ISSN = {1868-8969}, year = {2024}, volume = {288}, editor = {Murano, Aniello and Silva, Alexandra}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2024.37}, URN = {urn:nbn:de:0030-drops-196809}, doi = {10.4230/LIPIcs.CSL.2024.37}, annote = {Keywords: Conditional rewriting, Confluence, Program analysis} }
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