BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Jules Hedges (University and College Union) DTSTART:20220222T170000Z DTEND:20220222T180000Z DTSTAMP:20260423T021107Z UID:Intercats/4 DESCRIPTION:Title: Lenses and their generalisations: a guide to the design space\nby Ju les Hedges (University and College Union) as part of Intercats: Seminar on Categorical Interaction\n\n\nAbstract\nThe number of variants of lens-lik e structures\, plus some questionable terminology\, can seem overwhelming. I will tour some of the main variants\, with emphasis on exactly what con ditions on the base category are necessary for the construction\, and how they relate to each other. We will visit: (1) lenses over a cartesian cate gory\, (2) linear lenses over a monoidal closed category\, (3) optics over a monoidal category\, or more generally a pair of actegories\, (4) depend ent lenses over a category with pullbacks\, or more generally an indexed c ategory\, and (5) polynomial natural transformations over a locally cartes ian closed category. Unifying these motivates the problem of “dependent optics”\, which will be the topic of several future seminars.\n\nI am on strike action during this talk and I represent myself as an independent r esearcher\, not my employer. I will use some of my time to discuss this. M ore information about our grievances can be found here: https://www.ucu.or g.uk/article/11896/Why-were-taking-action\n LOCATION:https://researchseminars.org/talk/Intercats/4/ END:VEVENT END:VCALENDAR