Discrete mathematical modelling seminar

Seminar information archive ~04/23Next seminarFuture seminars 04/24~

Organizer(s) Tetsuji Tokihiro, Ralph Willox

2021/10/28

19:00-20:00   Online
This seminar will be held using Zoom. If you wish to participate, please contact R. Willox by email.
Andrew Hone (University of Kent)
Deformations of cluster mutations and invariant presymplectic forms
[ Abstract ]
We consider deformations of sequences of cluster mutations in finite type cluster algebras, which destroy the Laurent property but preserve the presymplectic structure defined by the exchange matrix. The simplest example is the Lyness 5-cycle, arising from the cluster algebra of type A_2: this deforms to the Lyness family of integrable symplectic maps in the plane. For types A_3 and A_4 we find suitable conditions such that the deformation produces a two-parameter family of Liouville integrable maps (in dimensions two and four, respectively). We also perform Laurentification for these maps, by lifting them to a higher-dimensional space of tau functions with a cluster algebra structure, where the Laurent property is restored. More general types of deformed mutations associated with affine Dynkin quivers are shown to correspond to four-dimensional symplectic maps arising as reductions of the discrete sine-Gordon equation.