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Copied image to imgur.com, as it was not being displayed because of the new https rule. Added link to original image source. Fixed redirected links.
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edit approved Nov 5, 2017 at 21:51
jeq
edit approved Nov 5, 2017 at 21:51
jeq
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Have a look at

(R. BROWNBrown, PP.R. HEATHHeath and H. KAMPSKamps), ``Groupoids"Groupoids and the Mayer-Vietoris sequence''sequence", J. Pure Appl. Alg. 30 (1983) 109-129.

A Mayer-Vietoris sequence for a pullback of a covering mao also appears in Section 10.7 of Topology and GroupoidsTopology and Groupoids, and was in the 1988 (differently named) edition.

 

Edit: Here is an extract from the above paper

mv http://pages.bangor.ac.uk/%7Emas010/gpds-mv.jpg (source)

which shows that there is some more information from the sequence than just the usual exact sequence. This sequence applies to spaces as is shown in Section 4 of the above paper. The point is that this detailed exactness is easier to extract in the groupoid model than directly in the topology.

Have a look at

(R. BROWN, P.R. HEATH and H. KAMPS), ``Groupoids and the Mayer-Vietoris sequence'', J. Pure Appl. Alg. 30 (1983) 109-129.

A Mayer-Vietoris sequence for a pullback of a covering mao also appears in Section 10.7 of Topology and Groupoids, and was in the 1988 (differently named) edition.

Edit: Here is an extract from the above paper

mv http://pages.bangor.ac.uk/%7Emas010/gpds-mv.jpg

which shows that there is some more information from the sequence than just the usual exact sequence. This sequence applies to spaces as is shown in Section 4 of the above paper. The point is that this detailed exactness is easier to extract in the groupoid model than directly in the topology.

Have a look at

(R. Brown, P.R. Heath and H. Kamps), "Groupoids and the Mayer-Vietoris sequence", J. Pure Appl. Alg. 30 (1983) 109-129.

A Mayer-Vietoris sequence for a pullback of a covering mao also appears in Section 10.7 of Topology and Groupoids, and was in the 1988 (differently named) edition.

 

Edit: Here is an extract from the above paper

(source)

which shows that there is some more information from the sequence than just the usual exact sequence. This sequence applies to spaces as is shown in Section 4 of the above paper. The point is that this detailed exactness is easier to extract in the groupoid model than directly in the topology.

added extra information about the exactness at the bottom end
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Ronnie Brown
Ronnie Brown
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Have a look at

(R. BROWN, P.R. HEATH and H. KAMPS), ``Groupoids and the Mayer-Vietoris sequence'', J. Pure Appl. Alg. 30 (1983) 109-129.

A Mayer-Vietoris sequence for a pullback of a covering mao also appears in Section 10.7 of Topology and GroupoidsTopology and Groupoids, and was in the 1988 (differently named) edition.

Edit: Here is an extract from the above paper

mv http://pages.bangor.ac.uk/%7Emas010/gpds-mv.jpg

which shows that there is some more information from the sequence than just the usual exact sequence. This sequence applies to spaces as is shown in Section 4 of the above paper. The point is that this detailed exactness is easier to extract in the groupoid model than directly in the topology.

Have a look at

(R. BROWN, P.R. HEATH and H. KAMPS), ``Groupoids and the Mayer-Vietoris sequence'', J. Pure Appl. Alg. 30 (1983) 109-129.

A Mayer-Vietoris sequence for a pullback of a covering mao also appears in Section 10.7 of Topology and Groupoids, and was in the 1988 (differently named) edition.

Have a look at

(R. BROWN, P.R. HEATH and H. KAMPS), ``Groupoids and the Mayer-Vietoris sequence'', J. Pure Appl. Alg. 30 (1983) 109-129.

A Mayer-Vietoris sequence for a pullback of a covering mao also appears in Section 10.7 of Topology and Groupoids, and was in the 1988 (differently named) edition.

Edit: Here is an extract from the above paper

mv http://pages.bangor.ac.uk/%7Emas010/gpds-mv.jpg

which shows that there is some more information from the sequence than just the usual exact sequence. This sequence applies to spaces as is shown in Section 4 of the above paper. The point is that this detailed exactness is easier to extract in the groupoid model than directly in the topology.

Source Link
Ronnie Brown
Ronnie Brown
  • 12.3k
  • 1
  • 63
  • 81

Have a look at

(R. BROWN, P.R. HEATH and H. KAMPS), ``Groupoids and the Mayer-Vietoris sequence'', J. Pure Appl. Alg. 30 (1983) 109-129.

A Mayer-Vietoris sequence for a pullback of a covering mao also appears in Section 10.7 of Topology and Groupoids, and was in the 1988 (differently named) edition.