Metamath Proof Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > MPE Home > Th. List > eqsstrd | Structured version Visualization version GIF version |
Description: Substitution of equality into a subclass relationship. (Contributed by NM, 25-Apr-2004.) |
Ref | Expression |
---|---|
eqsstrd.1 | ⊢ (𝜑 → 𝐴 = 𝐵) |
eqsstrd.2 | ⊢ (𝜑 → 𝐵 ⊆ 𝐶) |
Ref | Expression |
---|---|
eqsstrd | ⊢ (𝜑 → 𝐴 ⊆ 𝐶) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eqsstrd.2 | . 2 ⊢ (𝜑 → 𝐵 ⊆ 𝐶) | |
2 | eqsstrd.1 | . . 3 ⊢ (𝜑 → 𝐴 = 𝐵) | |
3 | 2 | sseq1d 3956 | . 2 ⊢ (𝜑 → (𝐴 ⊆ 𝐶 ↔ 𝐵 ⊆ 𝐶)) |
4 | 1, 3 | mpbird 256 | 1 ⊢ (𝜑 → 𝐴 ⊆ 𝐶) |
Copyright terms: Public domain | W3C validator |