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nLab > Latest Changes: absolute retract

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  1.  
    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeAug 20th 2019

    splitting off this definition from neighborhood retract, for ease of linking, and in order to record the characterization AR = ANR+contractible

    v1, current

    • CommentRowNumber2.
    • CommentAuthorUrs
    • CommentTimeMar 20th 2021

    added pointer to the original

    • {#Borsuk32} Karol Borsuk, Über eine Klasse von lokal zusammenhängenden Räumen, Fund. Math 19 (1932) 220-242 (dml:212574, pdf)

    and to

    diff, v3, current

    • CommentRowNumber3.
    • CommentAuthorUrs
    • CommentTimeMar 21st 2021

    I have added statement of the key examples (topological manifolds and locally finite CW complexes, both finite-dimensional) with references

    This now incorporates some but not yet all of Dmitri’s pointers here. Generally, there is much room to expand on this Examples-section. It looks like this page could be doing the world a favor by being the first source to state all this up-front.

    diff, v6, current

    • CommentRowNumber4.
    • CommentAuthorUrs
    • CommentTimeSep 19th 2021
    • (edited Sep 19th 2021)

    added pointer to

    and from this the proposition (now here) that all paracompact Banach manifolds are ANRs.

    diff, v8, current

1 to 4 of 4

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