of a topological space
A subset with the following property: There exists a homotopy of the identity mapping of to some mapping under which all points of the set remain fixed. If, under the homotopy, the points from remain in , is known as a strong deformation retract. A deformation retract of a space has the same homotopy type as does . See also Retract; Retract of a topological space.
Deformation retract. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Deformation_retract&oldid=15646