[math-fun] Pre-K Klein bottle puzzle
DanA: Consider the space Homeo(K) of self-homeomorphisms of the Klein bottle. I.e., Homeo(K) consists of all continuous bijections h : K —> K having a continuous inverse. __________ Umm, can somebody show me a continuous bijection with a *dis*continuous inverse? —rwg
Julian answered off-list: On the Klein bottle? No. Any continuous bijection of compact Hausdorff spaces has a continuous inverse. More generally? Sure. Take 0->0, n->1/n for n≥1 from the discrete space N to R; it's a continuous bijection onto its image, but the inverse is not continuous. Or take t->exp(2πit), from [0,1) to the unit circle. Julian On Thu, Dec 20, 2018 at 10:51 PM Bill Gosper <billgosper@gmail.com> wrote:
DanA: Consider the space Homeo(K) of self-homeomorphisms of the Klein bottle. I.e., Homeo(K) consists of all continuous bijections
h : K —> K
having a continuous inverse. __________ Umm, can somebody show me a continuous bijection with a discontinuous inverse? —rwg
Isn’t a pre-K Klein bottle a Jlein bottle?
On Dec 20, 2018, at 11:51 PM, Bill Gosper <billgosper@gmail.com> wrote:
DanA: Consider the space Homeo(K) of self-homeomorphisms of the Klein bottle. I.e., Homeo(K) consists of all continuous bijections
h : K —> K
having a continuous inverse. __________ Umm, can somebody show me a continuous bijection with a *dis*continuous inverse? —rwg _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
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Cris Moore