fact: Definition twoarrow_nt a u1 v1 u2 v2 r s := nttyd (twoarrow_fun_data a u1 v1) (twoarrow_fun_data a u2 v2) (fun x : (obsy twoarrow_data) => match x with o1 => r | o2 => s end).
imports: Arith cat_examples cardinal fc_limits