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UID:20250731T010254EDT-7569Vm8Bui@132.216.98.100
DTSTAMP:20250731T050254Z
DESCRIPTION:Title: Latent symmetry of graphs and stretch factors in Out(Fn)
 \n\nAbstract: Given an irreducible element of Out(Fn)\, there is a graph a
 nd an irreducible 'train track map' on this graph\, which induces the oute
 r automorphism on the fundamental group. The stretch factor of an outer au
 tomorphism measures the asymptotic growth rate of words in Fn under applic
 ations of the automorphism\, and appears as the leading eigenvalue of the 
 transition matrix of such an irreducible train track representative. I'll 
 present work showing a lower bound for the stretch factor in terms of the 
 edges in the graph and the number of folds in the fold decomposition of th
 e train track map. Moreover\, in certain cases\, a notion of the latent sy
 mmetry of a graph G gives a lower bound on the number of folds required fo
 r any train track map on G. I'll use this to classify all single fold irre
 ducible train track maps.\n\nAfter the talk\, we will gather for tea and s
 nacks in the lounge and then go for dinner with Paige.\n\n \n
DTSTART:20241106T210000Z
DTEND:20241106T220000Z
LOCATION:Room 920\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue 
 Sherbrooke Ouest
SUMMARY:Paige Hillen (UC Santa Barbara)
URL:/mathstat/channels/event/paige-hillen-uc-santa-bar
 bara-360878
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