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Schreibtisch.2.JPG Week-end editor:
Under the next months, I plan not to wikiedit substantially outside the weekends (Friday-monday). If you need to reach me in between, you may try wikimail!

A temporary font experiment: ℬ 𝒝 𝒝 𝒝 ℬ)

My name is Jörgen Backelin; I am a mathematician by profession; and have some side interests, like evolution theory, language history, and Scandinavian medieval ballads. My home page

My immediate reason for joining the Wikipedia community is that I feel that I might contribute by adding or improving some items in the mathematics section.

Some nice pages:[edit]

Some other useful links:[edit]

Other projects:[edit]

Less useful???

Ongoing or planned work[edit]

(you may add signed suggestions for getting my attention; but I won't promise to do anything about them)

Consider also missing parts of generating set; inspiration possible from older version.

Old undetected large scale acts of vandalism[edit]

In a couple of places, I have found large scale removals of sections, which were acts of pure vandalism. In those cases, the vandal replacements texts were removed later, but not the major part of the vandalised material. Viriditas has indicated that this is not a quite unique phenomenon, and that most such cases seem to have occurred in the years 2005 to 2008. Might be worth to look for - at least if anyhow I look at older versions.

The cases I know:

A propos the tsetse fly vandalism, User:Viriditas wrote: "I find this kind of thing quite a bit, and the problematic years appear to be 2005-2008."

Places where I've put questions, and should check up answers...[edit]

von Baer translations[edit]

From p. 200 in Über entwickelungsgeschichte der Tiere, 1827:

Nichts war leichter. Ein Fisch, der ans Land schwimmt, möchte dort gern spazieren gehn, wozu er seine Flossen nicht gebrauchen kann. Sie verschrumpfen in der Breite aus Mangel an Uebung und wachsen dagegen in die Länge. Das geht über auf Kinder und Enkel einige Jahrtausende hindurch. Da ist es dann kein Wunder, daß aus den Flosse zuletzt Füße werden. Noch natürlicher ist es, daß der Fisch auf der Wieße, da er kein Wasser findet, nach Luft schnappt. Dadurch triebt er endlich in einen eben so lange Frist Lungen hervor, wozu nur erfordert wird, daß einige Generationen sich unterdessen ohne Athmung behelfen.

Rough translation:

Nothing was easier. A fish which swims to the shore would like to go walkin' there, for which its fins are not useful. Those shrink in width, due to lack of training, and on the other hand grow in length. This passes over to children and further offspring during some millenia. Thus, there is no wonder, that the fins finally turn to feet. It is even more natural, that the fish in the meadow, where it does not find any water, [snappar efter; gasps for] air. Thereby, it eventually, after just a while, acquires lungs, where just a few generations must get by without breathing.

From p. 220, ibid.:

Eine bleibende thierform aber, welche den Typhus der Wirbelthiere hätte, und eine so geringe histologische und morphologische Sonderung, wie die Embryonen der Wirbelthiere, ist nicht bekannt. Mithin durchlaufe die Embryonen der Wirbelthiere in ihre Entwickelung gar kaine (bekannten) bleibenden Thierformen. [Emphasis in the original.]

Rough translation:

However, there is no known recent kind of animal of the vertebrates type and such a small [särprägel? difference? partition?] as that of the embryos of the vertebrates. Thus, in their development, the vertebrate embryos do not pass through a stage [representing] any (known) recent vertebrate.

From p. 257-258, ibid.:

Im Grunde hätte ich also die Ausdrücke Typus und Schema mit einem gemeinsamen vertauschen können. Ich habe sie nur aus einander gehalten, um eben dadurch recht geschaulich zu machen, daß jede organische Form, in Hinsicht des Typus, das was sie ist, durch die Art der Bildungsweise wird. Das Schema der Entwickelung ist nichts als der werdende Typus, und der Typus das Resultat des Bildungsschema.

Rough translation:

Thus, basically, I could have replaced the expressions type and schema with a common one. I have only kept them apart, in order thus to make it [överskådligt; transparent?], that with respect to the type what any organic form is it becomes by means of the ontogenesis.

(The story about the two confused embryos is printed in p. 221 of this work.)

Things someone probably should do something about; and possibly sometime in the future I might look at[edit]

  • Dimension versus Degrees of freedom (physics and chemistry). The latter replaced the former in Euclidean group (elsewhere??), and does not seem to contain any hint of the fact that this is one of the major ways mathematicians define dimension.
  • Relation algebra (suggested by Ramsey2006).
  • Declension (and some other grammar related articles), where sometimes clearer definitions are needed, and often better layperson exemplification.
  • Latin declension et al.: Case order; explaining cases; locative as a separate case or not.
  • Genomics, Human genome: Explain some of the most asked questions on e.g. the genetic background for sex distribution in human. Go back into history, find or make template, (re)insert information on the various sequenced genomes; readers will wish to be able to look them up.
  • Prime Minister of the Faroe Islands. I think all wcich may have wanted an opinion have expressed that in one or another WP; meaning essentially myself, User:Arne List, and User:Quackor; others have not responded. The list of older løgmenn absolutely not is a list of "prime ministers", in any sense. There are reasons to retain one list; although in some respects, the modern "løgmaður" more is a continuation of the "amtsmaður"; with the important distinction that the amtsmenn (like many of the older løgmenn but as distinct from the modern ones) were appointed from Denmark.
    Proposed remedy: Make a true article out of the present redirect page Løgmaður, treating the concept itself, and its historical development, and for the older part comparing with other Scandinavian lagmän ("law speakers"; note that at least one official English translation of a document mentioning them used the Danish lagman as English translation of løgmaður). Move the present article to List of løgmenn or something similar; and modify it slightly (removing the inference that the older ones were prime ministers, and referring to the new article). Make a redirect from the new Prime Minister of the Faroe Islands to Løgmaður. Fix the iw links; the split into one "ssubject article" and one "list" appears elsewhere, too. Finally, check infoboxes et cetera.
  • Category:Ethnologists vs. Category:Folklorists (with all their national subpages, and their sisters). Somewhat confused; fundamentally probably since the European colonialists could not consider study of "other kinds of humans" as on par with study of their own peoples.
  • The redirect pages Barycentre and Barycenter now are misleading. From my point of view, the best content would be the content of the present article Centroid, augmented with a few alternative meaning directs at the top. However, the word "centroid" feels a bit funny; I'd like to find an independent source for it to be the mainly used term, first. 18:16, 8 August 2010 (UTC)
  • Preadaption or exadaption should be explained or linked to; there are articles Exaptation and Preadaptation, though. A source: [1]. Check in OED and Dawkins for spellings with or without -at-! See also: User:Pengo/zoo. 20:52, 25 August 2011 (UTC)
  • There is some confusion about the terms Chaldean and Chaldian - at least in my mind:-). Attempts att "defusion":
    1. Chaldeans (sw. kaldéer) seemingly primarily refers to semitic-speaking people in Chaldea, in (or to?) the south of Mesopotamia, then close to the shore of the Persian Gulf. (The area includes the Sumerian city Ur, later taken by the Chaldeans.)
    2. Chaldians(?) (sw. Kalder), on the other hand, primarily relates to the people in Urartu, speaking a Hurrian related language. This area seemingly was centered at lake Van (which I thought was held by the Hittites - but perhaps that was slightly earlier?). Sources: The urartu articles in Svensk Uppslagsbok and in Encyclopædia Britannica, both in printed versions from the '50's.
    3. There is an article about Chalybes claiming that "in antiquity" (by which is meant Græco-Roman times), also called Chaldoi, which might treat the remnants of the Urartians, but seem to refer to an area centred more to the north; and which is included in our {{Kartvelians}}. (The latter is not necessarily completely out of the blue, even for Urartian; there are serious attempts to link Hurro-Urartian with some modern Caucasian languages; cf. Alarodian languages. On the other hand, neither that article, nor our main articles about Caucasian languages, nor (even implicitly) the template Kartvelian seems to link the Northeast Caucasian languages with Kartvelian. Is 'the Kartvelian-Hurro-Urartian connection' a 'discovery only valid for Georgians'?)
    4. We have no article, dab, or redir from "Chaldian". Our dab Chaldean starts "Chaldeans (or Chaldians) may refer to...", but contains no reference to Chaldians as defined supra. However, our Urartu article mentions the term Khaldian (which should be another spelling of Chaldian, I suppose), claiming that they called themselves Khaldini. We also have no asrticle, dab, or redib titled Khaldian.
All this is very confusing; and until to-day I had no idea that professional West Asia historians would make a distinction between the ancient Chaldeans and the ancient Chaldians. The terminology should be clarified - preferrably first finding out about possible deviations in modern terminology as compared to the 60 years old one, and appropriate cross references and "not to confuse with"'s should be inserted. It may also have some bearings on Ur Kaśdim. 21:45, 9 January 2014 (UTC)
  • "Evaluation function" does not lead to what I thought it would. I did find "the usual" (defined as the one I have used) meaning in Dual space, referred to as evaluation map. However, the latter term now redirects to initial topology, where it is employed for a kind of pullback. If something is done about "the usual meaning", then some link from the dab Evaluation (disambiguation) should be provided, and perhaps also comparisons with the Bra-ket notation, and discussions of LISPish Apply. 18:18, 22 October 2017 (UTC)

Missing mathematics related articles or links[edit]

At least partially fixed[edit]