Colouring finite planes of odd order

Finite Laguerre Near-planes of Odd Order Admitting Desarguesian Derivations

From this definition it readily follows that a Laguerre plane of order n has n + 1 generators, that every circle contains exactly n + 1 points and that there are n3 circles. All known models of finite Laguerre planes are of the following form. Let O be an oval in the Desarguesian projective plane P2 = PG(2, pm), p a prime. Embed P2 into threedimensional projective space P3 = PG(3, pm) and let v...

Point-primitive Inversive Planes of Odd Order

A famous but still unsolved problem in finite geometries is the question of whether a finite inversive plane J of odd order n is necessarily miquelian, that is, it arises from the plane sections of an elliptic quadric in PG(3,«). The question has been approached from different angles, and it has a positive answer if suitable conditions are added to J. The most classical result in this context i...

3 ODD ORDER PLANES 3 Result

Groups of generalised projectivities in projective planes of odd order

The generalised projectivities (GP's) associated with projective planes of odd order are investigated. These are non-singular linear mappings over GF(2) defined from the binary codes of these planes. One case that is investigated in detail corresponds to the group of an affine plane-every point corresponds to a GP. It is shown how many collineations that fix the line at infinity point-wise can ...

Colouring graphs with no odd holes

An odd hole in a graph is an induced subgraph which is a cycle of odd length at least five. In 1985, A. Gyárfás made the conjecture that for all t there exists n such that every graph with no Kt subgraph and no odd hole is n-colourable. We prove this conjecture.