Editing Automorphism (section)

==History==
One of the earliest group automorphisms (automorphism of a group, not simply a group of automorphisms of points) was given by the Irish mathematician [[William Rowan Hamilton]] in 1856, in his [[icosian calculus]], where he discovered an order two automorphism,<ref>{{Cite journal
|title=Memorandum respecting a new System of Roots of Unity
|author=Sir William Rowan Hamilton
|author-link=William Rowan Hamilton
|url=http://www.maths.tcd.ie/pub/HistMath/People/Hamilton/Icosian/NewSys.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.maths.tcd.ie/pub/HistMath/People/Hamilton/Icosian/NewSys.pdf |archive-date=2022-10-09 |url-status=live
|journal=[[Philosophical Magazine]]
|volume=12
|year=1856
|pages=446
}}</ref> writing:
<blockquote>so that <math>\mu</math> is a new fifth root of unity, connected with the former fifth root <math>\lambda</math> by relations of perfect reciprocity.</blockquote>