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semigroups
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Let RP2 denote the real projective plane (it can be obtained from glueing a Mobius band and a disk whose boundary is the same as the boundary of the Mobius band).
I know if one punches a hole off RP2 then the punched RP2 is homotopy equivalent to a Mobius band which is in turn deformable to a circle, I also know that RP2 is NOT deformable to a circle. Does this imply RP2 is not deformable to any of its proper subspaces? Otherwise by trasitivity of deformability one can imply RP2 is defromable to a circle which contradicts to the fact that it's not?
Morever, how about retractions? I know RP2 can NOT be retracted to a circle
I know if one punches a hole off RP2 then the punched RP2 is homotopy equivalent to a Mobius band which is in turn deformable to a circle, I also know that RP2 is NOT deformable to a circle. Does this imply RP2 is not deformable to any of its proper subspaces? Otherwise by trasitivity of deformability one can imply RP2 is defromable to a circle which contradicts to the fact that it's not?
Morever, how about retractions? I know RP2 can NOT be retracted to a circle