Warning: Table './church/sessions' is marked as crashed and last (automatic?) repair failed
query: SELECT sid FROM sessions WHERE sid = 'h53g1gjs3p8bu3fcjtvtq7hld1' in /var/www/church/includes/database.mysql.inc on line 121 Gruppo di Logica e Geometria della Cognizione
We explore a family of type isomorphisms in System F whose validity corresponds, semantically, to some form of the Yoneda isomorphism from category theory. These isomorphisms hold under theories of equivalence stronger than $\beta\eta$-equivalence, like those induced by parametricity and dinaturality. Based on such isomorphisms, we investigate a rewriting over types, that we call Yoneda reduction, which can be used to eliminate quantifiers from a polymorphic type, replacing them with a combination of monomorphic type constructors. We then demonstrate some applications of this rewriting to problems like counting the inhabitants of a type or characterizing program equivalence in some fragments of System F.
Warning: Can't find file: 'watchdog' (errno: 2)
query: INSERT INTO watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (0, 'php', 'Table './church/sessions' is marked as crashed and last (automatic?) repair failed\nquery: SELECT sid FROM sessions WHERE sid = 'h53g1gjs3p8bu3fcjtvtq7hld1' in /var/www/church/includes/database.mysql.inc on line 121.', 2, '', 'http://logica.uniroma3.it/calendario/2021/1/29', '', '216.73.216.58', 1751595691) in /var/www/church/includes/database.mysql.inc on line 121
Warning: Can't find file: 'watchdog' (errno: 2)
query: INSERT INTO watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (0, 'php', 'Table './church/sessions' is marked as crashed and last (automatic?) repair failed\nquery: INSERT INTO sessions (sid, uid, cache, hostname, session, timestamp) VALUES ('h53g1gjs3p8bu3fcjtvtq7hld1', 0, 0, '216.73.216.58', 'calendar_year|i:2021;calendar_mon|i:1;', 1751595691) in /var/www/church/includes/database.mysql.inc on line 121.', 2, '', 'http://logica.uniroma3.it/calendario/2021/1/29', '', '216.73.216.58', 1751595691) in /var/www/church/includes/database.mysql.inc on line 121