In
mathematics,
deformation theory is the study of
infinitesimal conditions associated with varying a solution
P of a problem to slightly different solutions
Pe, where e is a small number, or vector of small quantities. The infinitesimal conditions are therefore the result of applying the approach of
differential calculus to solving a problem with
constraints. One might think, in analogy, of a structure that is not completely rigid, and that deforms slightly to accommodate forces applied from the outside; this explains the name.