Any topology/homology expert present? It seems that this math.stackexchange.com/q/4412252/42969 is a duplicate since the question author posted an answer saying so. It is not my area of expertise, therefore I am reluctant to use my golden dup-hammer.
Not that I care about strange downvotes , but perhaps I miss something. Is anything wrong with this post, or is it just one of those "emotional" downvotes without any reason ?
@MartinR The question is a duplicate , unfortunately it has un upvoted answer , otherwise the author probably would already have deleted it.