Spans of delta lenses

Michael Johnson, Robert Rosebrugh

Research output: Contribution to journalConference paperpeer-review

6 Citations (Scopus)


As part of an ongoing project to unify the treatment of symmetric lenses (of various kinds) as equivalence classes of spans of asymmetric lenses (of corresponding kinds) we relate the symmetric delta lenses of Diskin et al, with spans of asymmetric delta lenses. Because delta lenses are based on state spaces which are categories rather than sets there is further structure that needs to be accounted for and one of the main findings in this paper is that the required equivalence relation among spans is compatible with, but coarser than, the one expected. The main result is an isomorphism of categories between a category whose morphisms are equivalence classes of symmetric delta lenses (here called fb-lenses) and the category of spans of delta lenses modulo the new equivalence.

Original languageEnglish
Pages (from-to)1-15
Number of pages15
JournalCEUR Workshop Proceedings
Publication statusPublished - 2015
EventInternational Workshop on Bidirectional Transformations (4th : 2015) - L'Aquila, Italy
Duration: 24 Jul 201524 Jul 2015


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