grey wanderer
bluewolfcub
right! can anyone help with the cone question
X is contractible <=> X is a retract of CX
I dont veen know where to start sweatdrop
X is contractible <=> X is a retract of CX
I dont veen know where to start sweatdrop
It's another definition game. I'd start by carefully writing out what it means for X to be a retract of CX. (in particlar, it means there is a function from f: CX->X with certain properties.) Then I would carefully write out the definition of CX. I claim that this function, f, tells you how to build a homotopy between X and a single point. Once you understand the proof in this direction, it should be fairly straight forward to go back in the other direction.
(I know my hints can be hard to follow sometimes, so feel free to ask for more details if this isn't enough to get you started)
yeah I'm still confused...
ah well I'll scribble something, I'm handing the stupid thing in today one way or another!
