BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20251104T070924EST-2615UV3HVE@132.216.98.100 DTSTAMP:20251104T120924Z DESCRIPTION:On the distribution of poles of rational solutions to the Painl eve II hierarchy\n\nThe second Painlevé equation admits a sequence of rati onal solutions that can be written as logarithmic derivatives of special e valuations of Schur polynomials associated to staircase-shaped integer par titions. These polynomials are known in the literature as Vorobev-Yablonsk y polynomials\, and their algebraic structure and asymptotic properties ar e fairly well understood. In particular\, Bertola and Bothner found that t he squares of these polynomials can be written as partition functions ((Ha nkel determinants) of a non-hermitian matrix model on a contour and theref ore their asymptotic behaviour may be investigated by the Deift-Zhou nonli near steepest descent method for Riemann-Hilbert problems. The limiting di stribution of the poles of the rational solutions is encoded into the geom etry of the steepest descent contours\, and the boundary of the pole accum ulation region can be characterized as the locus of points where the assoc iated algebraic curve changes its genus. The second Painlevé equation is t he first member of the Painlevé II hierarchy of integrable nonlinear ODEs. All members of the PII hierarchy admit a sequence of rational solutions\, and they are all expressible in terms of special evaluations of Schur pol ynomials associated to staircase partitions. The matrix model representati on of Bertola and Bothner generalizes naturally to all rational solutions of the PII hierarchy\, and the Deift-Zhou nonlinear steepest descent metho d offers an insight into the geometry of their limiting pole structure. In this talk I will introduce Schur polynomials associated to staircase part itions and explain their interpretation as matrix model partition function s. I will show how the Riemann-Hilbert method helps to explain the curious limiting shapes of the pole accumulation regions that were observed origi nally by Clarkson and Mansfield via numerical methods. The talk is based o n a joint work with M. Bertola and T. Bothner.\n DTSTART:20180306T203000Z DTEND:20180306T213000Z LOCATION:Room 4336\, CA\, Pav. André-Aisenstadt\, 2920\, ch. de la Tour SUMMARY:Ferenc Balogh\, John Abbott College et CRM URL:/mathstat/channels/event/ferenc-balogh-john-abbott -college-et-crm-285494 END:VEVENT END:VCALENDAR