2 papers
math.AC2010
New solutions to the Hurwitz problem on square identities
Anna Lenzhen, Sophie Morier-Genoud, Valentin Ovsienko
The Hurwitz problem of composition of quadratic forms, or of "sum of squares identity" is tackled with the help of a particular class of -graded non-associative a…
math.GT2010
Length of a curve is quasi-convex along a Teichmuller geodesic
Anna Lenzhen, Kasra Rafi
We show that for every simple closed curve α, the extremal length and the hyperbolic length of αare quasi-convex functions along any Teichmuller geodesic. As a corollary, we conclu…