BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20251105T165325EST-6727Nvxdmv@132.216.98.100 DTSTAMP:20251105T215325Z DESCRIPTION:Title:An invariant winding number for the FiztHugh-Nagumo syste m\n\nAbstract:\n\nThe FitzHugh-Nagumo system of partial differential equat ions (FHN) is a generic model for excitable media\, often used to build a qualitative understanding of electrophysiological phenomena. A well-charac terized traveling-pulse solution to FHN serves as a model for action poten tials in cardiac tissue and other contexts. The stability of the traveling pulse has been well-studied but the more global problem of predicting whe n an arbitrary initial condition will converge to the uniform rest solutio n and when it will converge to the traveling pulse remains unsolved. In th is talk\, I will present a proof of the existence of an invariant winding number in an asymptotic limit of the FHN system (the singular FHN system - SFHN) on a circular 1D domain that provides a crucial step toward a globa l convergence result. I will also provide evidence that this SFHN winding number result extends with limitations to FHN and outline conditions under which the SFHN approximation fails. The invariant winding number provides explanations for several observations of physiological relevance. For exa mple\, it explains the requirements on stimulus protocols that allow the f ormation and elimination of reentrant rhythms in cardiac tissue. This is j oint work with Kelly Paton.\n DTSTART:20181015T200000Z DTEND:20181015T210000Z LOCATION:Room 1104\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue Sherbrooke Ouest SUMMARY:Eric Cytrynbaum (UBC) URL:/mathstat/channels/event/eric-cytrynbaum-ubc-29048 8 END:VEVENT END:VCALENDAR