Venerdì 24 march 13:45-16:45
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
Constructibility and Forcing (Graduate course)
Alessandro Andretta
Mercoledì 22 march ore 15:00-17:00
in Aula 6 di Palazzo Campana [via Carlo Alberto 10]
in Aula 6 di Palazzo Campana [via Carlo Alberto 10]
Dual Ramsey Theory
Vojkan Vuksanovic
Venerdì 10 marzo ore 15:00--16:00 aula C
in Aula C di Palazzo Campana [via Carlo Alberto 10]
in Aula C di Palazzo Campana [via Carlo Alberto 10]
Finite state automata and monadic definability of ordinals
Itay Neeman (UCLA)
Venerdì 3 march 13:45-16:45
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
Constructibility and Forcing (Graduate course)
Alessandro Andretta
Mercoledì 1 march ore 14:00-16:00
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
Construction of non-conjugate actions (Part 2)
Asger Törnquist
Venerdì 24 febbraio ore 13:45-16:45
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
Introduction on PCF theory.
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
Constructibility and Forcing (Graduate course)
Alessandro AndrettaIntroduction on PCF theory.
Mercoledì 22 febbraio ore 14:00-16:00
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
It is a classical result that all conjugacy classes in the group of all measure preserving transformations on [0,1] are meagre, and that the generic transformation is ergodic. Foreman and Weiss showed that the conjugacy relation for ergodic transformations does not allow classification by countable structures, and more recently, Foreman, Weiss and Rudoplh showed that it is a complete analytic relation. In this talk, I will present a modest attempt at extending some of these results to actions of any countable group. We will show that every countable group has "E_0 many" ergodic measure preserving a.e. free actions on [0,1], thus showing that the conjugacy relation is never concretely classifiable. In particular, it follows that any countable group has continuum many such actions.
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
Construction of non-conjugate actions (Part 1)
Asger TörnquistIt is a classical result that all conjugacy classes in the group of all measure preserving transformations on [0,1] are meagre, and that the generic transformation is ergodic. Foreman and Weiss showed that the conjugacy relation for ergodic transformations does not allow classification by countable structures, and more recently, Foreman, Weiss and Rudoplh showed that it is a complete analytic relation. In this talk, I will present a modest attempt at extending some of these results to actions of any countable group. We will show that every countable group has "E_0 many" ergodic measure preserving a.e. free actions on [0,1], thus showing that the conjugacy relation is never concretely classifiable. In particular, it follows that any countable group has continuum many such actions.
Mercoledì 2 febbraio ore 14:00-16:00
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
We define barriers of trees and prove some theorems about them extending the results od Nash-Williams and Galvin and Prikry for integers to certain families of finite subtrees of an infinite, finitely branching tree without terminal nodes.
in Aula Lagrange di Palazzo Campana [via Carlo Alberto 10]
Barriers of trees
Vojkan VuksanovicWe define barriers of trees and prove some theorems about them extending the results od Nash-Williams and Galvin and Prikry for integers to certain families of finite subtrees of an infinite, finitely branching tree without terminal nodes.
Giovedì 13 ottobre ore 16:00--17:00 aula C
in Aula C di Palazzo Campana [via Carlo Alberto 10]
in Aula C di Palazzo Campana [via Carlo Alberto 10]