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Mar 19, 2021 at 18:11 comment added erz I did not claim it does. It's just a necessary condition
Mar 19, 2021 at 8:08 comment added Catologist_who_flies_on_Monday @erz I just noticed; this definition odes not guarantee that the extension has same modulus of continuity
Mar 16, 2021 at 17:42 comment added erz See for example Hatcher - Algebraic topology, chapter on homotopy groups
Mar 15, 2021 at 16:57 comment added Catologist_who_flies_on_Monday Oh ya? This is interesting. Would you happen to have a reference I could look in to?
Mar 15, 2021 at 16:47 comment added erz one of the definition of having vanishing $n-1$-th homotopy group is precisely existence of extension of any continuous map $f:S^{n-1}\to Y$ to $F:D_{n}\to Y$
Mar 15, 2021 at 11:02 history edited YCor CC BY-SA 4.0
removed capitals from title
Mar 15, 2021 at 10:23 comment added Catologist_who_flies_on_Monday I added the requested clarification. However, I don't see the homotopic argument.
Mar 15, 2021 at 10:22 history edited Catologist_who_flies_on_Monday CC BY-SA 4.0
added 117 characters in body
Mar 15, 2021 at 6:12 comment added erz If $X$ is the sphere, then possibility of extension means that $n-1$-th homotopy group of $Y$ vanish. Also, it doesn't say in the body of the question that modulus of continuity has to be preserved (as you mentioned in the title). Could you please clarify?
Mar 14, 2021 at 18:41 history edited Catologist_who_flies_on_Monday CC BY-SA 4.0
edited title
Mar 14, 2021 at 18:32 history asked Catologist_who_flies_on_Monday CC BY-SA 4.0