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I hope someone improves this article so that it defines the Veblen function. Right now it simply seems to state a bunch of properties of this function, without asserting that some set of properties characterizes it. John Baez (talk) 06:08, 4 November 2012 (UTC)
In the lead it gives the general definition, "If φ0 is any normal function, then for any non-zero ordinal α, φα is the function enumerating the common fixed points of φβ for β<α.". In the first section, it defines "Veblen hierarchy" by specifying that "In the special case when φ0(α)=ωα, this family of functions is known as the Veblen hierarchy.". JRSpriggs (talk) 10:15, 4 November 2012 (UTC)