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We have just started logging errors. On this page, you will find information about all errors that persisted on the site for more than one month on any page. Note: This applies only to errors that were not fixed by December 18, 2011. Errors fixed before then are not being logged on this page.
|Page||Error description||Version where it was introduced||Version where it was corrected||Why error? Why not caught? ("I" refers to Vipul)|
|Space of path components||Incorrect statement that induced multiplication on space of path components gives a topological monoid structure; in fact it need not be continuous||December 20, 2010||July 6, 2019||genuine conceptual confusion|
|Compact times paracompact implies paracompact||General sloppiness in proof, missed some inclusion conditions||June 3, 2017||Additional conditions were implicit when reading; carelessness in review|
|Homotopy type of connected sum depends on choice of gluing map||Excluded one relation from cohomology ring description||July 29, 2011||December 15, 2016||Ignored interaction term in analysis|
|Connected sum of two complex projective planes with opposite orientation||Excluded one relation from cohomology ring description||July 29, 2011||December 15, 2016||Ignored interaction term in analysis|
|Connected sum of two complex projective planes with same orientation||Excluded one relation from cohomology ring description||July 29, 2011||December 13, 2016||Ignored interaction term in analysis|
|Paracompact Hausdorff implies normal||Used instead of at one place||May 30, 2016||Didn't proofread carefully|
|Locally path-connected space||Incorrectly said it is obtained by applying the locally operator||May 30, 2016||Multiple definitions of "locally" floating around|
|Homotopy of spheres, homotopy of real projective space, homotopy of complex projective space||Stated that some groups are when all we know is that sometimes they are infinite.||April 2016||Difficult topic, basically just guesswork/poor sourcing|
|Hausdorffization||provided incorrect definition that seemed prima facie plausible||November 15, 2015||genuine knowledge gap, common confusion|
|Weak homotopy equivalence of topological spaces||provided incorrect definition in the form of "induces isomorphisms on and on homology"||November 18, 2013||genuine knowledge gap, common confusion.|
|Double mapping cylinder||wrote instead of .||November 2, 2007||February 11, 2014||Typo, didn't proofread.|
|Manifold||mistakenly wrote "equivalent" for a bunch of conditions all of which need to be satisfied.||November 2, 2014||Typo, didn't proofread.|
|Jointly continuous map||typo: wrote that slice topology is finer than slice topology, meant it is finer than product topology||December 20, 2010||May 15, 2015||Typo, didn't proofread, and didn't revisit the page.|