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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.

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