**Prolongation 101**

A whiteboard talk given at the Mini-workshop on Geometric Analysis,
University of Wollongong, 5th September 2014

**Abstract** Prolongation is a process for augmenting a system
of partial differential equations with further equations in order to produce
an equivalent but more congenial system. This talk will be a beginner's guide
starting with what turns out to be the Killing equation in Euclidean space.
Prolongation is often regarded as more of an art than a science but, with the
advent of parabolic geometry, some theory can be constructed.

At the talk I handied out (insufficiently many copies of)

T.P. Branson, A. Čap, M.G. Eastwood, and A.R. Gover,
Prolongations of geometric overdetermined systems,
Internat. Jour. Math. 17 (2006) 641-664,

M.G. Eastwood,
Prolongations of linear overdetermined systems on affine and
Riemannian manifolds,
Rend. Circ. Mat. Palermo Suppl. 75 (2005) 89-108,

the second of which is a more expository version of the first with more
examples. Please
let me know
if you would like hard copies. Here are my

very rough notes for the talk.