Some wiki engines offer markup for superscript and subscript text.

==Proposed markups==

===Superscript===

%%(vertical-align: sup) Superscripted %% text

Creole: {{{ ^^This is superscripted text^^ }}}

Proposed XHTML: {{{ <sup> </sup> }}}

Comparison:
http://www.wikimatrix.org/syntax.php?i=28

===Subscript===

%%(vertical-align: sub) Subscripted text %%

Creole: {{{ ~~This is subscripted text~~ }}} or {{{ ,,This is subscripted text,, }}}

Note: the use of double-tilde may conflict with [[Escape Character Proposal]]

Proposed XHTML: {{{ <sub> </sub> }}}

Comparison on wikimatrix:
http://www.wikimatrix.org/syntax.php?i=29

==Rationale==

===Use cases===
* Superscript
** Basic maths
** Units of measurement (e.g. square meter - m²)
** Large numbers, metric scientific notation (e.g. 1,253x10²³)
** Ordinal numbers (e.g. 1^^st^^, 2^^nd^^, 18^^th^^ century, in French 1^^er^^, 2^^e^^, 18^^e^^ siècle)
** Possibly for footnotes (shouldn't it be handled by another mechanism than what is considered, in that particular case, as a presentation markup)
** Many indexed terms in science (like n^^+^^)


* Subscript
** Basic maths
** Basic chemistry
** Much of biology (gene names, etc.)

===Alternatives===
* Unicode digits
* Specialized markup languages like MathML, ChemML and LaTeX
than as part of formulas.


===Advantages===
* Simple way to insert superscripted/subscripted text
* The users don't have to learn a new language.
* Super- and subscript are basic functions in most word processors
* Super- and subscript almost always have a semantic value, rather than being a formatting issue.
* Depending on the software/keyboard layout, it might be very difficult or impossible to insert Unicode superscript or subscript digits.
* Unicode digits:
** are limited to... digits! - thus covering only a small subset of use cases
** The presentation of successive Unicode digits is not always appropriate (see above of this source).
* MathML etc. is necessary for specialized applications, especially in Math. However:
** complex formulas were historically expensive, and use in engineering and science therefore limited. Invention of symbols involving the no-cost super and subscript was much more frequent.
** In practive, MathML etc. is not currently supported, and does not correspond with the frequency of use of super- and subscript in engineering and science.
* Inline with [Cover the common things people need|Goals] (is it?) - Yes!
* NotNew, a lot of wiki engines offer markup for superscript and subscript text. HTML offers it.

===Disadvantages===
* [Better] alternatives exist
** Please elaborate which alternatives are available in which Wiki software
* New markups to learn - NotNew though.
* Markup characters can be hard to find on several keyboard layouts