BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Jules Hedges (Max Planck Institute) DTSTART:20200415T170000Z DTEND:20200415T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/1 DESCRIPTION:Title: Open games: the long road to practical applications\nby Jules He dges (Max Planck Institute) as part of ACT@UCR\n\n\nAbstract\nI will talk about open games\, and the closely related concepts of lenses/optics and o pen learners. My goal is to report on the successes and failures of an ong oing effort to try to realise the often-claimed benefits of categories and compositionality in actual practice. I will introduce what little theory is needed along the way. Here are some things I plan to talk about:\n\n\n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Michael Shulman (University of San Diego) DTSTART:20200422T170000Z DTEND:20200422T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/2 DESCRIPTION:Title: Star-autonomous envelopes\nby Michael Shulman (University of San Diego) as part of ACT@UCR\n\n\nAbstract\nSymmetric monoidal categories wi th duals\, a.k.a. compact monoidal categories\, have a pleasing string dia gram calculus. In particular\, any compact monoidal category is closed wi th $[A\,B] = (A^* \\otimes B)$\, and the transpose of $A \\otimes B \\to C $ to $A \\to [B\,C]$ is represented by simply bending a string. Unfortuna tely\, a closed symmetric monoidal category cannot even be embedded fully- faithfully into a compact one unless it is traced\; and while string diagr am calculi for closed monoidal categories have been proposed\, they are mo re complicated\, e.g. with "clasps" and "bubbles". In this talk we obtain a string diagram calculus for closed symmetric monoidal categories that l ooks almost like the compact case\, by fully embedding any such category i n a star-autonomous one (via a functor that preserves the closed structure ) and using the known string diagram calculus for star-autonomous categori es. No knowledge of star-autonomous categories will be assumed.\n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Gershom Bazerman DTSTART:20200429T170000Z DTEND:20200429T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/3 DESCRIPTION:Title: A localic approach to the semantics of dependency\, conflict\, and c oncurrency\nby Gershom Bazerman as part of ACT@UCR\n\n\nAbstract\nPetr i nets have been of interest to applied category theory for some time. Bac k in the 1980s\, one approach to their semantics was given by algebraic ga dgets called "event structures." We use classical techniques from order th eory to study event structures without conflict restrictions (which we ter m "dependency structures with choice") by their associated "traces"\, whic h let us establish a one-to-one correspondence between DSCs and a certain class of locales. These locales have an internal logic of reachability\, w hich can be equipped with "versioning" modalities that let us abstract awa y certain unnecessary detail from an underlying DSC. With this in hand we can give a general notion of what it means to "solve a dependency problem" and combinatorial results bounding the complexity of this. Time permittin g\, I will sketch work-in-progress which hopes to equip these locales with a notion of conflict\, letting us capture the full semantics of general e vent structures in the form of homological data\, thus providing one avenu e to the topological semantics of concurrent systems. This is joint work w ith Raymond Puzio.\n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Sarah Rovner-Frydman (Marlboro College) DTSTART:20200506T170000Z DTEND:20200506T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/4 DESCRIPTION:Title: Separation logic through a new lens\nby Sarah Rovner-Frydman (Ma rlboro College) as part of ACT@UCR\n\n\nAbstract\nSeparation logic aims to reason compositionally about the behavior of programs that manipulate sha red resources. When working with separation logic\, it is often necessary to manipulate information about program state in patterns of deconstructio n and reconstruction. This achieves a kind of "focusing" effect which is s omewhat reminiscent of using optics in a functional programming language. We make this analogy precise by showing that several interrelated techniqu es in the literature for managing these patterns of manipulation can be de rived as instances of the general definition of profunctor optics. In doin g so\, we specialize the machinery of profunctor optics from categories to posets and to sets. This simplification makes most of this machinery look more familiar\, and it reveals that much of it was already hiding in sepa ration logic in plain sight.\n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Tai-Danae Bradley (CUNY Graduate Center) DTSTART:20200513T170000Z DTEND:20200513T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/5 DESCRIPTION:Title: Formal concepts vs. eigenvectors of density operators\nby Tai-Da nae Bradley (CUNY Graduate Center) as part of ACT@UCR\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Gordon Plotkin (University of Edinburgh) DTSTART:20200520T170000Z DTEND:20200520T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/6 DESCRIPTION:Title: A complete axiomatisation of partial differentiation\nby Gordon Plotkin (University of Edinburgh) as part of ACT@UCR\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Nina Otter (UCLA) DTSTART:20200603T170000Z DTEND:20200603T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/7 DESCRIPTION:Title: Values and inclusivity in the Applied Category Theory community\ nby Nina Otter (UCLA) as part of ACT@UCR\n\n\nAbstract\nSaddened by the cu rrent events\, we are taking this opportunity to pause and reflect on what we can do to change the status quo and try to bring about real and long-l asting change. \n\nThus\, we are holding a discussion aimed at finding con crete solutions to make the Applied Category Theory community more inclusi ve\, and also to reflect about the values that our community would like to stand for and endorse\, in particular\, in terms of which sources of fund ing go against our values. While this discussion is specific to the applie d category theory community\, we believe that many of the topics will be o f interest also to people in other fields\, and thus we welcome anybody wi th an interest to attend. The discussion will consist of two parts: we wil l have first several people give short talks to discuss common issues that we need to address\, as well as present specific plans for initiatives th at we could take. We believe that the current pandemic\, and the fact that all activities are now taking place remotely\, gives us the opportunity t o involve people who would otherwise find it difficult to travel\, because of disabilities\, financial reasons or care-taking responsibilities. Thus \, now we have the opportunity to come up with new types of mentoring\, co llaborations\, and many other initiatives that might have been difficult t o envision until just a couple of months ago. The second part of the discu ssion will take place on the category theory community server\, and its pu rpose is to allow for a broader participation in the discussion\, and idea lly during this part we will be able to flesh out in detail the specific i nitiatives that have been proposed in the talks.\n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Prakash Panangaden (McGill) DTSTART:20200408T170000Z DTEND:20200408T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/8 DESCRIPTION:Title: A categorical view of conditional expectation\nby Prakash Panang aden (McGill) as part of ACT@UCR\n\n\nAbstract\nThis talk is a fragment fr om a larger work on approximating Markov processes. I will focus on a func torial definition of conditional expectation without talking about how it was used. We define categories of cones---which are abstract versions of t he familiar cones in vector spaces---of measures and related categories co nes of Lₚ functions. We will state a number of dualities and isomorphism s between these categories. Then we will define conditional expectation by exploiting these dualities: it will turn out that we can define condition al expectation with respect to certain morphisms. These generalize the sta ndard notion of conditioning with respect to a sub-sigma algebra. Why did I use the plural? Because it turns out that there are two kinds of conditi onal expectation\, one of which looks like a left adjoint (in the matrix s ense not the categorical sense) and the other looks like a right adjoint. I will review concepts like image measure\, Radon-Nikodym derivatives and the traditional definition of conditional expectation. This is joint work with Philippe Chaput\, Vincent Danos and Gordon Plotkin. \n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Simon Willerton (University of Sheffield) DTSTART:20200527T170000Z DTEND:20200527T180000Z DTSTAMP:20260404T094545Z UID:ACTUCR/9 DESCRIPTION:Title: The Legendre–Fenchel transform from a category theoretic perspecti ve\nby Simon Willerton (University of Sheffield) as part of ACT@UCR\n\ nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/ACTUCR/9/ END:VEVENT END:VCALENDAR