# CorrectionMatrix -- determines the first order deformations used in correcting liftings

## Description

CorrectionMatrix is the name of an optional argument, whose value is either with value auto or of the form output by correctionMatrix. The second term in the sequence is a list of two matrices which give some parameter-free first-order deformations and the corresponding lifted relations, respectively. The first term in the sequence is , which describes the action on liftings of equations by the specified first-order deformations. If set to auto, correctionMatrix is used to calculate the relevant sequence. The default value of CorrectionMatrix is auto.

## Functions with optional argument named CorrectionMatrix :

• "localHilbertScheme(...,CorrectionMatrix=>...)" -- see localHilbertScheme -- computes a power series representation of the local Hilbert scheme
• "versalDeformation(...,CorrectionMatrix=>...)" -- see versalDeformation(Matrix) -- computes a power series representation of a versal deformation

## For the programmer

The object CorrectionMatrix is .