Metamath Proof Explorer


Theorem scottrankd

Description: Rank of a nonempty Scott's trick set. (Contributed by Rohan Ridenour, 11-Aug-2023)

Ref Expression
Hypothesis scottrankd.1 φ B Scott A
Assertion scottrankd φ rank Scott A = suc rank B

Proof

Step Hyp Ref Expression
1 scottrankd.1 φ B Scott A
2 scottex2 Scott A V
3 2 rankval4 rank Scott A = x Scott A suc rank x
4 3 a1i φ rank Scott A = x Scott A suc rank x
5 1 adantr φ x Scott A B Scott A
6 simpr φ x Scott A x Scott A
7 5 6 scottelrankd φ x Scott A rank B rank x
8 6 5 scottelrankd φ x Scott A rank x rank B
9 7 8 eqssd φ x Scott A rank B = rank x
10 9 suceqd φ x Scott A suc rank B = suc rank x
11 10 iuneq2dv φ x Scott A suc rank B = x Scott A suc rank x
12 1 ne0d φ Scott A
13 iunconst Scott A x Scott A suc rank B = suc rank B
14 12 13 syl φ x Scott A suc rank B = suc rank B
15 4 11 14 3eqtr2d φ rank Scott A = suc rank B