Difference between revisions of "Deformation retraction/Definition"

Revision as of 20:08, 11 May 2016

Definition

A subspace, $A$, of a topological space $(X,\mathcal{ J })$ is called a deformation retract of $X$, if there exists a retraction^[1], $r:X\rightarrow A$, with the additional property:

• $i_A\circ r\simeq\text{Id}_X$^[1]

Caution:Be sure to see the warnings on terminology

References

1. ↑ ^{Jump up to: 1.0 1.1} An Introduction to Algebraic Topology - Joseph J. Rotman