Editing Mathematical folklore (section)

{{Short description|Communally-attributed mathematical results}}
{{other uses of|folk theorem|Folk theorem (disambiguation)}}

In common mathematical parlance, a mathematical result is called '''folklore''' if it is an unpublished result with no clear originator, but which is well-circulated and believed to be true among the specialists. More specifically, '''folk mathematics''', or '''mathematical folklore''', is the body of theorems, definitions, proofs, facts or techniques that circulate among mathematicians by word of mouth, but have not yet appeared in print, either in books or in scholarly journals.<ref name=":1">{{Cite web|url=https://ncatlab.org/nlab/show/folklore|title=folklore in nLab|website=ncatlab.org|access-date=2019-11-30}}</ref>

Quite important at times for researchers are '''folk theorems''', which are results known, at least to experts in a field, and are considered to have established status, though not published in complete form.<ref name=":1" /> Sometimes, these are only alluded to in the public literature. 
An example is a book of exercises, described on the back cover:
{{quote|This book contains almost 350 exercises in the basics of [[ring theory]]. The problems form the "folklore" of ring theory, and the solutions are given in as much detail as possible.<ref>Grigore Calugareau & Peter Hamburg (1998) ''Exercises in Basic Ring Theory'', Kluwer,[{{isbn|0792349180}}]</ref>}}

Another distinct category is '''well-knowable''' mathematics, a term introduced by [[John Horton Conway|John Conway]].<ref>[[J. W. S. Cassels]] (1976) "An embedding theorem for fields: Addendem", ''Bulletin of the [[Australian Mathematical Society]]'' 14: 479–80 {{doi|10.1017/S0004972700025442}}</ref> These mathematical matters are known and factual, but not in active circulation in relation with current research (i.e., untrendy). Both of these concepts are attempts to describe the actual context in which research work is done.

Some people, in particular non-mathematicians, use the term ''folk mathematics'' to refer to the [[informal mathematics]] studied in many ethno-cultural studies of mathematics.{{Citation needed|date=September 2019}} Although the term "mathematical folklore" can also be used within the mathematics circle to describe the various aspects of their esoteric culture and practices (e.g., slang, proverb, limerick, joke).<ref>{{Cite web|url=https://www.ams.org/notices/200501/fea-dundes.pdf|title=Foolproof: A Sampling of Mathematical Folk Humor|last1=Renteln|first1=Paul|last2=Dundes|first2=Alan|date=|website=American Mathematical Society|archive-url=|archive-date=|access-date=2019-11-29}}</ref>