Universal updates for symmetric lenses

Michael Johnson, Robert Rosebrugh

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

4 Citations (Scopus)
7 Downloads (Pure)


Asymmetric c-lenses are the special cases of asymmetric d-lenses (also called delta lenses) whose updates satisfy a universal property which in many applications ensures "least-change". There has therefore been hope that symmetric c-lenses might characterize those symmetric dlenses which satisfy a similar universal property. This paper begins an analysis of symmetric c-lenses and their relationship to symmetric dlenses and explains why the authors do not expect symmetric c-lenses, that is, equivalence classes of spans of c-lenses, to be central to developing universal properties for symmetric lenses. Instead, we consider cospans of c-lenses and show that they generate symmetric c-lenses with an appropriate universal property. That property is further analysed and used to motivate proposed generalisations to obtain universal, least-change, properties for symmetric d-lenses. In addition we explore how to characterise the symmetric d-lenses that arise from cospans of c-lenses among all symmetric d-lenses.

Original languageEnglish
Title of host publicationBX 2017: Bidirectional Transformations
Subtitle of host publicationProceedings of the 6th International Workshop on Bidirectional Transformations
EditorsRomina Eramo, Michael Johnson
Place of PublicationAachen
PublisherRheinisch-Westfaelische Technische Hochschule Aachen
Number of pages15
ISBN (Electronic)9783319574189
ISBN (Print)9783319574172
Publication statusPublished - 2017
EventInternational Workshop on Bidirectional Transformations (6th : 2017) - Uppsala, Sweden
Duration: 29 Apr 201729 Apr 2017

Publication series

NameCEUR workshop proceedings
ISSN (Electronic)1613-0073


ConferenceInternational Workshop on Bidirectional Transformations (6th : 2017)

Bibliographical note

Copyright by the paper's authors. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


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