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    • CommentRowNumber501.
    • CommentAuthorTim_Porter
    • CommentTimeFeb 27th 2015
    • (edited Feb 27th 2015)

    The other two are from which is a known Ukrainian spam address. (Can someone more knowledgeable please check this out. It seems to be a bot / spider.) I will clear the two pages and send them to ‘empty’. (143 and 144)

    • CommentRowNumber502.
    • CommentAuthorTobyBartels
    • CommentTimeMar 19th 2015

    The wp-login pages are probably automatic attempts from a bot to gain access to our hypothetical WordPress installation.

    • CommentRowNumber503.
    • CommentAuthorTim_Porter
    • CommentTimeMay 6th 2015

    I emptied a page F-theory - From11dSupergravity which seemed to be spammed. It is now empty 146.

    • CommentRowNumber504.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 4th 2015

    Seems to be spam again, see latest revisions, probably from ’Computer Science’ up to ’mylab Classical dynamics books’.

    • CommentRowNumber505.
    • CommentAuthorTim_Porter
    • CommentTimeSep 6th 2015
    • (edited Sep 6th 2015)

    Usually I delete and empty such entries, but in this case I was waiting to see if whoever had created the ‘mylab’ pages had some useful intent behind their attempt. What do others think? As David_C says, the entries start at Computer Science then mylab and so on, and at all from anon1 at, who is in Egypt it seems.

    • CommentRowNumber506.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 6th 2015

    I think it’s spam. I never can quite remember what exactly we do. Is there a recipe we could write somewhere?

    • CommentRowNumber507.
    • CommentAuthorTim_Porter
    • CommentTimeSep 6th 2015
    • (edited Sep 6th 2015)

    I will try to remember… although sometimes I get it wrong. :-(

    A problem can arise if the page really was spamming something already written, so check the page did not have a History first. If it did exist prior to the Spamming, revert to the latest unspammed version. If not then you delete the contents, check the last number used on an ’empty’ file, (currently 146) and change the name on the offending file to the next (’empty 147’). (I think that is all, but am sure that others will check on what I have said.) Oh! remember the obvious thing that renaming a page will create a redirect so go back and clear that as well.

    • CommentRowNumber508.
    • CommentAuthorDavidRoberts
    • CommentTimeSep 6th 2015

    What Tim has outlined is what I recall Toby recommending to do in these cases.

    • CommentRowNumber509.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 8th 2015

    Ok, thanks. So empty 147-151 are born.

    • CommentRowNumber510.
    • CommentAuthorTim_Porter
    • CommentTimeSep 8th 2015

    Thanks, David, I usually do this but am travelling and was busy. I have also to prepare the the meeting in Paris at the end of the month!

    • CommentRowNumber511.
    • CommentAuthorDavidRoberts
    • CommentTimeSep 9th 2015

    The page meta topological space looks exceeding flaky to me. Not sure what to do about it. Not sure it’s quite spam, but certainly no good in its current state. The author, ’D. Ely’ has also made Meta matrices, which is likewise very odd.

    • CommentRowNumber512.
    • CommentAuthorTim_Porter
    • CommentTimeSep 10th 2015

    Both look ’flaky’ to me. Perhaps put a polite warning notice on the shorter one giving a time limit for the author to explain what is intended on these pages. What do you think?

    • CommentRowNumber513.
    • CommentAuthorTodd_Trimble
    • CommentTimeSep 10th 2015

    My own opinion, for what it’s worth, is that it’s not worth it spending any time dealing with the author. I would just get rid of them.

    • CommentRowNumber514.
    • CommentAuthorDavidRoberts
    • CommentTimeSep 10th 2015

    Thanks, Todd, I agree. That meta topological space one is particularly useless.

    • CommentRowNumber515.
    • CommentAuthorTobyBartels
    • CommentTimeOct 18th 2015

    One addition to Tim's directions in #507: You should be able to quickly see how high up the empty pages go by checking But this only works if you make the content of the new empty pages read

    category: empty

    instead of being literally empty! I have done this up to empty 152 now.

    • CommentRowNumber516.
    • CommentAuthorUrs
    • CommentTimeOct 19th 2015

    I have cleared “meta topological space” and have renamed “Meta matrices” to hypermatrix, which is a term that is pretty standard in the context of discussion of hyperdeterminants.

    • CommentRowNumber517.
    • CommentAuthorTodd_Trimble
    • CommentTimeOct 19th 2015

    I added a reference to hyperdeterminants, linking to an MO discussion of volume interpretations of hyperdeterminants.

    • CommentRowNumber518.
    • CommentAuthorzskoda
    • CommentTimeOct 19th 2015
    • (edited Oct 19th 2015)

    516: I disagree that hypermatrix is another term for tensor in more than 2 dimensions. It is equally wrong as claiming that an ordinary matrix is a tensor. Quadratic matrix can represent a tensor in particular basis, but the matrix does not know its origin. It does not know if it represents a covariant 2-tensor, or contravariant 2-tensor or mixed 1-1-tensor, and so on, nor it knows in which basis this representation is taken, hence it is not giving the complete information on a tensor. It is frosen datum of a tensor provided we know the basis. If we do not have this supplementary datum then it is not.

    I am on the other hand not sure if the term is used for non-quadratic matrices of higher number of indices/dimensions.

    • CommentRowNumber519.
    • CommentAuthorUrs
    • CommentTimeOct 20th 2015

    Sure, basis representations. I have added the word to the entry.

    • CommentRowNumber520.
    • CommentAuthorTobyBartels
    • CommentTimeNov 8th 2015

    Fundamentally, an mm-by-nn matrix with entries from the set KK is an element of K m×K nK^m \times K^n, which is not any sort of tensor. However, if KK is a field and you wish to add and multiply the matrices in the usual way, then an nn-by-nn matrix is a (1,1)(1,1)-tensor on K nK^n, with multiplication given by contraction. Since K nK^n comes with a preferred basis, you can interpret such a matrix as a (0,2)(0,2)-tensor or a (2,0)(2,0)-tensor, but this is less direct. This is why people sometimes use the word ‘matrix’ to refer to a (1,1)(1,1)-tensor, even though that is (strictly speaking) improper. (Dually, people sometimes use the word ‘vector’ to refer to a list.)

    Why are we discussing this in the Spam thread?

    • CommentRowNumber521.
    • CommentAuthorzskoda
    • CommentTimeJan 18th 2016

    I got serious spam from IP with stupid Russian texts overwriting all my text, today, on 09:57 January 18 on HomePage (zoranskoda) and homotopija lekcija2 (zoranskoda). I rolled it back.

    • CommentRowNumber522.
    • CommentAuthorDavidRoberts
    • CommentTimeFeb 14th 2016
    • (edited Feb 14th 2016)

    The page Algebres enveloppantes (Cahiers scientifiques, fasc. 37) (French Edition) (French) Paperback – 1974 (created by an Anon Coward at looks to me like the filename of a torrent-sourced copy of a book. In this case, it’s a book by Dixmier, and the title of that page could have been copied verbatim from this Amazon page.

    • CommentRowNumber523.
    • CommentAuthorTobyBartels
    • CommentTimeMay 20th 2016

    I made that last one a real page and linked to it from universal enveloping algebra.

    • CommentRowNumber524.
    • CommentAuthorTim_Porter
    • CommentTimeSep 4th 2017
    • (edited Sep 4th 2017)

    Mysterious spam from 2405:204:8485:ab49:a8f3:c856:6f17:9f86 at floor. It just says ’3.6’.

    What is that type of identifier as a search did not produce any results?

    • CommentRowNumber525.
    • CommentAuthorAlexisHazell
    • CommentTimeSep 4th 2017

    It’s an IPv6 address.

    • CommentRowNumber526.
    • CommentAuthorTobyBartels
    • CommentTimeOct 1st 2017
    • (edited Oct 1st 2017)

    I put some content at floor. (Such content may be discussed in a separate discussion.)

    • CommentRowNumber527.
    • CommentAuthorRichard Williamson
    • CommentTimeApr 15th 2018
    • (edited Apr 15th 2018)

    Unclear whether it is technically spam, but have deleted a page ’real line and circle with one point remove is homeomorphic’ created today (its only content was a copy of the title), as well as the announcement which it generated on the nForum.

  1. Deleted page created with ’(X,d) is a pseudometric Hausdorff space…’ in the title, with content a proof of this. Have noted down IP address and author (joeljoeljoel). I believe that the same page may have existed before (which I deleted). I also deleted the thread with the nForum announcement of the page creation, amongst other reasons to avoid making it possible to create the page simply by clicking on the links in the announcement.

    • CommentRowNumber529.
    • CommentAuthorMike Shulman
    • CommentTimeMay 21st 2018

    This is a strange sort of spam.

    • CommentRowNumber530.
    • CommentAuthorTobyBartels
    • CommentTimeAug 29th 2018

    Some automated scripts may attempt to create spam that, thanks to Instiki's quirks or our filters, ends up not really working. (For instance, if there was supposed to be spam link in a user homepage field and the script makes the post even though we don't have such a field, although this is just my speculation.)

    As to whether we should be deleting such spam, much less things are not even clearly spam as in the previous few comments, that's being discussed elsewhere.

    • CommentRowNumber531.
    • CommentAuthorDavid_Corfield
    • CommentTimeNov 26th 2018

    We seem to be receiving spam attacks. Look at the latest additions for Kalb-Ramond field (by Edward Witten!), Hilbert module, circle action, Roger Penrose.

    Sometimes a page appears not to be changed, e.g., the last version of From String structures to Spin structures on loop spaces by Britney. I guess they could change a web address and it wouldn’t show.

    We do need to keep an eye on latest changes. Looking back what’s this at contact instanton? Seems that someone just filled in a link there.

    I don’t have time right now to roll these back. Can we find out if these changes are coming from the same place?

  2. I have blocked in nginx the IP address which the two entries I checked were edited from. No time to look further into it or doing any rolling back. Let me know if there are other IP address which should be blocked (the IP address can be seen by looking at the History of the page).

    • CommentRowNumber533.
    • CommentAuthorTim_Porter
    • CommentTimeNov 27th 2018

    I rolled back Kalb-Ramond field.

    • CommentRowNumber534.
    • CommentAuthorTim_Porter
    • CommentTimeNov 27th 2018
    • (edited Nov 27th 2018)

    I rolled back Hilbert module There was a change made to the Context part of it with what looked like a suspicious link. The change was: by Sara Seger on November 26, 2018 at 16:22:57 from as well. From the same IP address was circle action, as David C noticed and I rolled that back as well.

    • CommentRowNumber535.
    • CommentAuthorUrs
    • CommentTimeNov 27th 2018

    Thanks, everyone! Yes, let’s keep an eye on LatestChanges.

  3. I have deleted the spam edits from the database now. Felt this was important to keep things clean, especially the one with ’Edward Witten’ as author. Have also deleted the page ’contact instanton’ and the corresponding nForum thread.

    • CommentRowNumber537.
    • CommentAuthorTim_Porter
    • CommentTimeDec 21st 2018

    Spam on HomePage. I will roll back. It is from

  4. Thanks. Have deleted the revision and your rollback now. Not blocked IP address for the moment, but have noted it. Will block given a second occurrence.

    • CommentRowNumber539.
    • CommentAuthorTim_Porter
    • CommentTimeFeb 24th 2019

    Spam at Bluevhale. The address ( is in Turkey. I have left it to others to delete this properly.

  5. Blocked IP address which had rolled back the pages Freyd cover and adjoint functor, and had made several edits to the Sandbox. Both rollbacks and all other edits have been deleted.

    Also blocked the IP address mentioned at and deleted the created page Bluevhale (no other edits had been made with this IP).

    Cleaned up the nForum afterwards.

    I do begin to think that we must do something about anonymous edits, maybe making them ’pending’ or something.

    • CommentRowNumber541.
    • CommentAuthorTim_Porter
    • CommentTimeMar 14th 2019

    see simplicial complex. Revision 39 was spammed and the page overwritten by

  6. Thanks Tim! I have deleted that revision now, so Revision 39 is just your rollback, i.e. is identical to Revision 38. I have also blocked the IP address.

  7. Deleted new spam at quantum information, and removed traces of spam from earlier this year. One of the ’sophisticated’ attacks where blocking IP address will not work. Added content to spam filter, but the text was changed this time compared to the previous attempts.

  8. Removed some spam from the Latest Changes thread for bitcoin.

    • CommentRowNumber545.
    • CommentAuthorRodMcGuire
    • CommentTimeSep 25th 2019
    • (edited Sep 25th 2019)

    Anonymous has added and had removed 3 times a spam link in An Essay on the Foundations of Geometry

    nforum thread for that page

    maybe should be added to the spam filter.

  9. Addressed now,

    • CommentRowNumber547.
    • CommentAuthorUrs
    • CommentTimeSep 28th 2019

    Just for the record: the account just spammed half a dozen nForum threads.

  10. Blocked the account and cleaned up the spam now.

    • CommentRowNumber549.
    • CommentAuthorAlexisHazell
    • CommentTimeNov 13th 2019

    I’ve now added “Tango” and “tango” to the spam filter - a cursory Wikipedia search didn’t indicate any mathematics-related meanings, but please let me know if this causes any issues.

    • CommentRowNumber550.
    • CommentAuthorMike Shulman
    • CommentTimeNov 14th 2019

    We should also blank or remove the nLab pages.

    • CommentRowNumber551.
    • CommentAuthorAlexisHazell
    • CommentTimeNov 14th 2019

    @Mike Shulman, re. #3: Yeah, I was wondering about that. :-) Which is preferable?

    • CommentRowNumber552.
    • CommentAuthorUrs
    • CommentTimeNov 14th 2019

    For standard uncontroversially clear-cut malicious spam we should delete the pages for good, with no trace in the history left.

    Others here (Toby) have used to urge that as soon as there is a shred of possibility that something is meant as an actual contribution, and be it as obnoxious as it may, then we should keep it in the History. And I see that point, given what’s going on in the world.

    But standard malicious commercial spam is uncontroversially recognized and should be deleted for good.

    • CommentRowNumber553.
    • CommentAuthorAlexisHazell
    • CommentTimeNov 14th 2019

    @Urs, re. #5: Okay, so on the basis that the two ’Tango’-related pages are clearly inappropriate for the nLab, I’ve now deleted the relevant pages from the database. Thanks!

    • CommentRowNumber554.
    • CommentAuthorRichard Williamson
    • CommentTimeNov 15th 2019
    • (edited Nov 15th 2019)

    Thanks Alexis! Yes, I always delete pages/revisions in these circumstances to keep the history clean, and also delete the corresponding nForum threads usually. Just in case you need it, this is the procedure I follow for deleting nLab pages.

    1) Look up the id in the pages table. E.g. something like SELECT * FROM pages WHERE name=’xxx’

    2) Do DELETE FROM revisions WHERE page_id=xxx

    3) Do DELETE FROM wiki_references WHERE page_id=xxx

    4) Do DELETE FROM pages WHERE id=xxx

    For deleting an nForum thread, I delete both the discussion and any comments with that discussion id.

    For instance I think I saw recently an example where Rod rolled back some spam. I would usually delete that revision (and the rollback) in the database to keep the history clean.

    • CommentRowNumber555.
    • CommentAuthorRichard Williamson
    • CommentTimeNov 15th 2019
    • (edited Nov 17th 2019)

    Just in case you were not already aware, one needs to restart the nLab server for spam filter changes to take effect by the way (/bin/unicornctl restart). There is no downtime with these restarts. Apologies if you already figured this out, but I thought I’d mention it!

    • CommentRowNumber556.
    • CommentAuthorAlexisHazell
    • CommentTimeNov 16th 2019


    re. #7:

    Thanks - I’d done the deletions from ’pages’ and ’revisions’, but I hadn’t thought to check ’wiki_references’, and I wasn’t sure whether to delete the relevant nForum threads as well. In this particular instance, should we keep both threads, since non-spam discussion has been had in them?

    re. #8:

    Oh, I was indeed not aware of that - thanks for bringing it to my attention!

  11. Removed page with title ’antiderivative’ with spam content from IP 2600:8802:5902:e600:b1ba:8912:6dfd:f3ed, along with corresponding created nForum thread.

  12. Comments #549 - #556 were originally in a different thread created by the edit announcer upon creation of a spam page with title ’Tango support center’. Moving here to allow deletion of the original thread (which I have now done).

    Hope this resolves your question in #556 satisfactorily, Alexis!

    If I remember I usually make a note of spam deletions in this thread here.

  13. Hi Alexis,

    I forgot one more thing that I do as part of the deletion procedure: to remove the page from the cache. E.g. rm www/nlab-prod/cache/views/nlab/show/xxx. Some other things are also sometimes cached, e.g. history and revision pages, but those are viewed less often, and I sometimes don’t bother with those; just have a look around in the cache directories :-).

    • CommentRowNumber560.
    • CommentAuthorAlexisHazell
    • CommentTimeDec 16th 2019

    Removed nForum spam about tech support, added relevant word to spam filter.

  14. I have deleted a page with title ’Every discrete topological space Is locally connected space’ with similar one-line content. I believe this was ’accidental spam’. Urs had made a small edit to the page to try to make it more reasonable, but Todd agreed with deletion, so I am going ahead and doing so.

  15. Deleted a page ’Set theory proof’ which was the same kind of thing as in #561.

  16. Deleted a page with title ’URL’ and no content.

  17. Deleted a page ’Fréchet spaces is not banach space’ and its associated nForum thread. Similar cases to the above.

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