Metamath Proof Explorer


Theorem weeq2

Description: Equality theorem for the well-ordering predicate. (Contributed by NM, 3-Apr-1994)

Ref Expression
Assertion weeq2 ( 𝐴 = 𝐵 → ( 𝑅 We 𝐴𝑅 We 𝐵 ) )

Proof

Step Hyp Ref Expression
1 freq2 ( 𝐴 = 𝐵 → ( 𝑅 Fr 𝐴𝑅 Fr 𝐵 ) )
2 soeq2 ( 𝐴 = 𝐵 → ( 𝑅 Or 𝐴𝑅 Or 𝐵 ) )
3 1 2 anbi12d ( 𝐴 = 𝐵 → ( ( 𝑅 Fr 𝐴𝑅 Or 𝐴 ) ↔ ( 𝑅 Fr 𝐵𝑅 Or 𝐵 ) ) )
4 df-we ( 𝑅 We 𝐴 ↔ ( 𝑅 Fr 𝐴𝑅 Or 𝐴 ) )
5 df-we ( 𝑅 We 𝐵 ↔ ( 𝑅 Fr 𝐵𝑅 Or 𝐵 ) )
6 3 4 5 3bitr4g ( 𝐴 = 𝐵 → ( 𝑅 We 𝐴𝑅 We 𝐵 ) )