Reputation
8,605
Next privilege 10,000 Rep.
Access moderator tools
Badges
1 18 24
Newest
 Guru
Impact
~182k people reached

  • 0 posts edited
  • 0 helpful flags
  • 39 votes cast
Feb
15
answered Universal covering space of CW complex has CW complex structure
Feb
11
comment What does it mean to attach a cell to a space by a map?
Thanks: correction made. You can also look at my book "Topology and groupoids" advertised at pages.bangor.ac.uk/~mas010/topgpds.html .
Feb
11
revised What does it mean to attach a cell to a space by a map?
typo in link
Feb
11
answered Isomorphism between fundamental groups.
Feb
9
revised Fundamental groupoids is a embedding of category $Cov(B)\to Cov(\Pi(B))$
added a reference
Feb
9
revised Fundamental groupoids is a embedding of category $Cov(B)\to Cov(\Pi(B))$
given a fuller answer
Feb
8
answered Fundamental groupoids is a embedding of category $Cov(B)\to Cov(\Pi(B))$
Feb
3
revised What does it mean to attach a cell to a space by a map?
clarification and also a remark on history and "meaning"
Feb
2
revised What does it mean to attach a cell to a space by a map?
typo
Feb
2
revised What does it mean to attach a cell to a space by a map?
typo
Feb
2
answered What does it mean to attach a cell to a space by a map?
Jan
30
revised Should a high school introductory calculus class teach $\varepsilon$-$\delta$ proofs?
added a link and more info on a book
Jan
25
revised fundamental group of the complement of a circle
clarification of book titles
Jan
25
answered fundamental group of the complement of a circle
Jan
21
revised Why does Seifert-Van Kampen not hold with $n$-th homotopy groups?
replaced "question 2" by "questions 1,2$
Jan
21
revised Why does Seifert-Van Kampen not hold with $n$-th homotopy groups?
typo
Jan
21
revised Why does Seifert-Van Kampen not hold with $n$-th homotopy groups?
expanded previous account
Jan
20
comment The Seifert-Van Kampen theorem as a push-out
Since you ask for free further reading I mention this paper: pages.bangor.ac.uk/~mas010/pdffiles/brown-razak.pdf which gives the statement for a general cover and a set of base points, and the proof by verification of the universal property. This is the proof that generalises to higher dimensions. For a discussion, see pages.bangor.ac.uk/~mas010/pdffiles/galway7.pdf
Jan
20
revised Why does Seifert-Van Kampen not hold with $n$-th homotopy groups?
added more comment
Jan
20
answered Why does Seifert-Van Kampen not hold with $n$-th homotopy groups?