Deformation retraction/Definition
From Maths
Definition
A subspace, [ilmath]A[/ilmath], of a topological space [ilmath](X,\mathcal{ J })[/ilmath] is called a deformation retract of [ilmath]X[/ilmath], if there exists a retraction[1], [ilmath]r:X\rightarrow A[/ilmath], with the additional property:
- [ilmath]i_A\circ r\simeq\text{Id}_X[/ilmath][1]
- Caution:Be sure to see the warnings on terminology
