BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Sonja Hohloch (University of Antwerp) DTSTART:20210323T180000Z DTEND:20210323T190000Z DTSTAMP:20260423T035030Z UID:OSGA/53 DESCRIPTION:Title: On recent advances in semitoric integrable systems\nby Sonja Hohloch (Un iversity of Antwerp) as part of Online Seminar "Geometric Analysis"\n\n\nA bstract\nRoughly speaking\, a semitoric system is a completely integrable Hamiltonian system on a 4-dimensional symplectic manifold that admits only nondegenerate singularities without hyperbolic components and whose flow gives rise to an $(\\mathbb S^1 \\times \\mathbb R)$-action. Coupled spin oscillators and coupled angular momenta are examples of such semitoric sys tems.\n\nSemitoric systems have been symplectically classified about a dec ade ago by Pelayo $\\&$ Vu Ngoc by means of five invariants. Recently\, th ere has been made considerable progress by various authors concerning the computation of these invariants.\n\nIn this talk\, we will give an introdu ction to semitoric systems before considering a recent\, intuitive family of semitoric systems that allows for explicit observation of bifurcation b ehaviour such as bifurcations between focus-focus and elliptic-elliptic si ngularities and other interesting geometric-topological features related t o singularities and bifurcations. The latter part is based on a joint work with A.\\ De Meulenaere.\n LOCATION:https://researchseminars.org/talk/OSGA/53/ END:VEVENT END:VCALENDAR