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APLAS 2020
Mon 30 November - Wed 2 December 2020
Wed 2 Dec 2020 18:30 - 19:00 at online - Semantics Chair(s): Florian Rabe

\emph{Monad algebras}, turning computations over return values into values, are used to resolve algebraic effects invoked by programs (effect handling), whereas \emph{comonad coalgebras}, turning initial states into cocomputations over states, are used to specify production of environments with coalgebraic coeffects (coeffect production). \emph{(Monad-comonad) interaction laws} by Katsumata et al. describe interaction protocols between a computation and a cocomputation. We show that any triple of those tools can be combined into a single algebra handling computations over state predicates. This method yields an isomorphism between the category of interaction laws, and the category of so-called \emph{merge functors} which merge algebras and coalgebras to form combined algebras. In a similar vein, we can combine interaction laws with coalgebras only, retrieving Uustalu’s stateful runners. If instead we combine interaction laws with algebras only, we get a novel concept of continuation-based runners that lift a cocomputation of value predicates to a single predicate on computations of values. We use these notions to study different running examples of interactions of computations and cocomputations.

Wed 2 Dec

Displayed time zone: Osaka, Sapporo, Tokyo change

17:30 - 19:00
SemanticsResearch Papers at online
Chair(s): Florian Rabe University of Erlangen
17:30
30m
Talk
Certified Semantics for Relational Programming
Research Papers
Dmitry Rozplokhas Higher School of Economics and JetBrains Research, Russia, Andrey Vyatkin Saint Petersburg State University, Russia, Dmitri Boulytchev Saint Petersburg State University / JetBrains Research
18:00
30m
Talk
An Abstract Machine for Strong Call by Value
Research Papers
Malgorzata Biernacka University of Wroclaw, Dariusz Biernacki University of Wrocław, Witold Charatonik Institute of Computer Science, University of Wroclaw, Tomasz Drab Institute of Computer Science, University of Wroclaw
18:30
30m
Talk
Algebraic and coalgebraic perspectives on interaction laws
Research Papers
Tarmo Uustalu Reykjavik University, Niels Voorneveld Tallinn University of Technology