Hypercascading Hyper Notation (HpCHN) is the 13th part of HN.
An expression is of the form H_m<n,A>, where n is the base, m is the secondary base, and A is an array.
Y = X_Y<1>. Any X_Y<0> can be removed.
X<X_Y<A-1>,B> (for B < X_Y<A>) = X<X_Y<A-1>> = X_(X_Y<A-1>) = X_Y<A-1>
Define # is rest of array.
If A is a sequence array:
X<X_Y<A-1>,N+X_Y<A>> (where N is any array) is the cascader of X<X_Y<A-1>,N+A> (where A < X_Y<A>), that means it copies X<X_Y<A-1>,N+A> and not [A].
X<X_Y<A-1>,B> (where B is sequence array) is the cascader of X<X_Y<A-1>+C,B-1> (where C is an array), that means it copies X<X_Y<A-1>+C,B-1> and not [C].
Now, Define X_Y<A>is a Y-cascader of X<X_Y<A-1>,N>, that means it uses X<X_Y<A-1>,N> and not X<N>.
If A is a limit array:
X_Y<A> is a Y-cascader of X<X_Y<FS(A,x)>>, that means it uses X<X_Y<FS(A,x)>> and not X<N>.