CANCELLED - Joint Colloquium: Baird -- What is the shape of a finite graph?

CANCELLED due to illness of speaker (as notified by Emma Carberry)

Abstract:  The fundamental theorem of axonometry of Gauss, affirms that
if we project a cube in R3 onto the complex plane in such a way that one
of its vertices is projected to the origin, then the three neighbouring
vertices are projected to complex numbers whose sum of squares is zero.
This result is generalized by M. Eastwood and R. 
Penrose, who show that the projection of the vertices of any Platonic
solid into the plane satisfy a certain quadratic equation.  This
motivates the study of a class of quadratic equations on a graph; in
particular to see how the existence of solution relate to the structure
of the graph.


Paul Baird

Universit\’e de Brest

(visiting A.N.U.)