Innocent Strategies are Sheaves over Plays

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• Takeshi Tsukada (University of Oxford)
• Friday 12 December 2014, 12:00-13:00
• Arts - Lecture Room 201.

If you have a question about this talk, please contact Neel Krishnaswami.

Although the HO/N games are fully abstract for PCF , the traditional notion of innocence (which underpins these games) is not satisfactory for such language features as non-determinism and probabilistic branching, in that there are stateless terms that are not innocent. Based on a category of P-visible plays with a notion of embedding as morphisms, we propose a natural generalisation by viewing innocent strategies as sheaves over (a site of) plays, echoing a slogan of Hirschowitz and Pous. Our approach gives rise to fully complete game models in each of the three cases of deterministic, nondeterministic and probabilistic branching. To our knowledge, in the second and third cases, ours are the first such factorisation-free constructions.

This talk is part of the Theoretical computer science seminar series.

This talk is included in these lists:

• Arts - Lecture Room 201
• Computer Science Departmental Series
• Computer Science Distinguished Seminars
• Theoretical computer science seminar
• computer sience

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