Y = (X ∪ I)/{x0 ~ 0} (disjoint union) xo - base point in X(adsbygoogle = window.adsbygoogle || []).push({});

I am trying to show that X is a deformation retract of Y.

I understand I need to maps f:X -> Y and g:Y -> X and show homotopic equivalence

Where f is the inclusion map, is the identity ok for f?

i.e f:X->Y , x in X -> x in Y

What is appropriate for g? Is the idea to map all of I in Y to x0 in X?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Deformation retract

**Physics Forums | Science Articles, Homework Help, Discussion**