At: fun enumer 1 2 1 1 1
1. n: 
2. m: 
3. 0 < m
4. f: (
(m-1)

n)

(n
m-1)
5. Bij(
(m-1)

n;
(n
m-1); f)
6. n = 0
Bij(
m

n;
(n
m);
z.z(0))
By:
Unfold `biject` 0
THEN
Analyze 0
Generated subgoals:1 | Inj( m  n; (n m); z.z(0)) |
2 | Surj( m  n; (n m); z.z(0)) |
About: