Giovedì 10 Luglio 2025 dalle ore 10:30, nel quadro del ciclo di seminari Al@Bicocca, Arnaud Brothier (University of Trieste and UNSW Sydney) e Ryan Seelig (UNSW Sydney) terranno i seguenti interventi
Relatore: Arnaud Brothier
Titolo: Vaughan Jones’ reconstruction program and infinite groups
Abstract: In his quest in constructing conformal field theories (CFT) from subfactors Vaughan Jones found an unexpected connection with Richard Thompson’s group T. This led to Jones’ technology: a powerful method for constructing actions of certain groups. I will present the great lines of Jones’ fascinating connection and will mention various applications of it in group theory, (operator) algebras and so on. I will end by introducing forest-skein groups which sit at the intersection of all these areas and ideas.
Relatore: Ryan Seelig
Titolo: Finitely presented simple groups with no piecewise projective actions
Abstract: Following on from the previous talk, we investigate an explicit class of examples of forest-skein (FS) groups. We show they act naturally on the circle by orientation-preserving homeomorphisms, are finitely presented, and are simple. Surprisingly, we will show these examples admit no piecewise projective, and hence no piecewise affine, actions on the circle. This is in stark contrast to previous examples of such simple groups in the literature. Finally, using powerful dynamical techniques of Rubin and McCleary, we are able to distinguish infinitely many isomorphism classes in our class of examples. This is joint work with Arnaud Brothier.
Informazioni per partecipare
I seminari si terranno in Aula 3014 (3° Piano - Edificio U5), Dipartimento di Matematica e Applicazioni e sarà possibile partecipare anche online da questo link
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