Proof step

Ore-algebra identity of two definitions

All-n equality of two definitions

Concludes

shift_x_plus_one of Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having genus k (see first comment for definition of genus).

Premises

none: a direct theorem check

Theorem

polytool ?

Checked

polytool replayed · Lean not attempted