User blog comment:Syst3ms/Breadth-Recursive Array Notation (BRAN)/@comment-25601061-20180424215049/@comment-35392788-20180425205307

Well, I can just define h(n) as C(n,n,...,n) and then define D(a,b,c,...) the same way I did for C, i.e

D(a,b,c) = h(C(a,b,c))

All previous rules apply.

And that's when I feel like I can diagonalize through this to get ω^2.

For that, I would do this :

$$A_0(a,b,c,...) = B(a,b,c,...)$$