lentic catachresis
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 Mar15 answered How to prove a Set category with at least one element is a separator? Mar15 reviewed Reject Why is the partial derivative $f_x' = 0$ is not continous? Mar15 revised If a morphism of pushouts of complexes (with one arrow monic) is composed of quasi-isos, then the induced arrow is one also added 526 characters in body; edited title Mar14 comment If a morphism of pushouts of complexes (with one arrow monic) is composed of quasi-isos, then the induced arrow is one also Thank you. I will read your answer with detail later. I was just aware of "homotopy colimits" in the category of topological spaces, not in any more general sense. Mar14 comment If a morphism of pushouts of complexes (with one arrow monic) is composed of quasi-isos, then the induced arrow is one also @ZhenLin: Thanks. I'll roll up my sleeves and diagram-chase in that particular case then, I guess. I'm intrigued about your comment about homotopy colimits though, if you would like to expand on it (maybe as an answer?) it would be great :) Mar14 comment If a morphism of pushouts of complexes (with one arrow monic) is composed of quasi-isos, then the induced arrow is one also @Zhen: What if one of the arrows is a monomorphism (in the case of the pushout)? Mar14 asked If a morphism of pushouts of complexes (with one arrow monic) is composed of quasi-isos, then the induced arrow is one also Mar14 comment Mayer-Vietoris Type Sequence For Pushouts One little comment. A nice reference for homotopy pushouts/pullbacks is Arkowitz's Introduction to homotopy theory. In particular, the second sentence of your second paragraph is proposition 6.2.6. Mar12 reviewed Approve Probability of at least one male and one female sharing the same birthday Mar10 comment Simply connected reduced suspension on path connected X @JuanS: I haven't read the posts in detail, but in the first one the counterexample he produces involved the Hawaiian earring which does not satisfy the hypotheses of Freudenthal's suspension theorem. Mar6 awarded Nice Answer Feb24 reviewed Reject What makes a limit 'go away'? Feb24 reviewed Reject truth tables and validity of arguments Feb23 comment The fundamental group of a topological group is abelian Hey, cute abstract nonsense proof! Thanks for posting it! (+1) Feb21 accepted Is an integer a sum of two rational squares iff it is a sum of two integer squares? Feb18 reviewed Reject Differentiable function on bad sets. Feb10 reviewed Approve Evaluating $\int\frac{3x+1}{2x^2-2x+3}dx$ Feb8 reviewed Approve At least one prime between N and N-(sqrtN) Feb7 comment The groups $[\Sigma^nX,Y]$ versus the homotopy groups @nik: I understand what you're saying now. But the questions are the end are to be taken to mean: "in these circumstances, does the knowledge of these groups for all $X$ give us information?" (the questions you linked being taking $X=S^0$) Feb7 comment The groups $[\Sigma^nX,Y]$ versus the homotopy groups @nik: as interesting as those questions may be, I don't see any reference to the groups I allude to in this one.