User blog comment:Tetramur/BEAF above SVO - comparison/@comment-5150073-20200219121934/@comment-35470197-20200220135159

> I need your help in ordinals

Sure.

> What is Omega^^Omega in terms of psi function? I thought it is zeta_(Omega + 1) but I missed, I think, 'cause I think it is much larger.

I think that I am not understand the meaning of the question. If you are considering Buchholz's function, then we have Do they include what you want to know?
 * Ω^Ω = ψ_1(ψ_1(ψ_1(0)))
 * ζ_{Ω+1} = ψ_1(ψ_2(ψ_2(0)))
 * ψ(Ω^Ω) = Γ_0.
 * ψ(ζ_{Ω+1}) = ψ(Ω_2) = BHO

> I need some help with Veblen function of three arguments and Saibian's expressions.

I can tell you 3-ary Veblen function, but I know few about Saibian's expressions.