Source: wikibot/bachmann-howard-ordinal

= Bachmann–Howard ordinal
{wiki=Bachmann–Howard_ordinal}

The Bachmann–Howard ordinal, often denoted as \\( \\Theta \\), is a significant ordinal number in set theory and the foundations of mathematics. It arises in the context of proof theory, particularly with respect to the analysis of the consistency of various formal systems, such as arithmetic and set theory. The Bachmann–Howard ordinal serves as a specific metric for measuring the strength of certain proofs and the provability of statements in formal systems.