Talk:Additively indecomposable ordinal

Multiplicative indecomposability of 2
Toshiyasu Arai says in [ Arai, A sneak preview of proof theory of ordinals (p.7)] the quote "every multiplicative principal number $$\alpha=\omega^{\omega^\beta}$$ is ...". Is 2 considered multiplicatively indecomposable, but not multiplicatively principal? C7XWiki (talk) 22:34, 25 January 2021 (UTC)

History section
I'd like to see a brief section "History" in the article, mentioning who came up with the concept, and linking to a primary source. - Jochen Burghardt (talk) 16:35, 10 August 2021 (UTC)