- :Michael Hardy mentions that this is part of the mathematical folklore.
- Guy's observation has since become part of mathematical folklore, and is commonly referenced by other authors.
- Another term used for informal mathematics is "'folk mathematics "', which is ambiguous; the mathematical folklore article is dedicated to the usage of that term among professional mathematicians.
- In mathematical folklore, the "'" no free lunch " theorem "'( sometimes pluralized ) of David Wolpert and William Macready appears in the 1997 " No Free Lunch Theorems for Optimization ".
- As the term is understood by mathematicians, "'folk mathematics "'or "'mathematical folklore "'is the body of theorems, definitions, proofs, or mathematical facts or techniques that circulate among mathematicians by word of mouth but have not appeared in print, either in books or in scholarly journals.