e/Bachmann-Howard ordinal

Information
has gloss	eng: In mathematics, the Bachmann–Howard ordinal (or Howard ordinal) is a large countable ordinal. It is the proof theoretic ordinal of several mathematical theories, such as Kripke–Platek set theory (with the axiom of infinity) and the system CZF of constructive set theory. It is named after William Alvin Howard and Heinz Bachmann.
lexicalization	eng: Bachmann-Howard ordinal
lexicalization	eng: Bachmann–Howard ordinal
instance of	(noun) the number designating place in an ordered sequence ordinal number, no., ordinal