Editing Iteration mark (section)

== Superscript numeral ==

In western mathematics, the superscript numeral originated as a notation for exponentiation.<ref>{{cite book |last1=Cajori |first1=F |title=A History of Mathematical Notation Vol. 1 |date=1928 |publisher=The Open Court Publishing Company |location=La Salle, Illinois |page=346}}</ref> Over time its meaning expanded to represent repeated function application as well, effectively making it a notation for marking iteration.<ref>{{cite book |last1=Cajori |first1=F |title=A History of Mathematical Notation Vol. 2 |date=1929 |publisher=The Open Court Publishing Company |location=La Salle, Illinois |page=176}}</ref> This sense was eventually borrowed in non mathematical text to represent repeated symbols, especially to mark repeated letters in acronyms. The superscript is occasionally left out, either colloquially or in the formal representation of the acronym, due to either typographic or stylistic concerns. Notable examples include the bus protocol [[I²C]], and the fan-fiction hosting website [[AO3]].