Description: Equality theorem for function value, analogous to fveq2 . (Contributed by AV, 4-Sep-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | afv2eq2 | ⊢ ( 𝐴 = 𝐵 → ( 𝐹 '''' 𝐴 ) = ( 𝐹 '''' 𝐵 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eqidd | ⊢ ( 𝐴 = 𝐵 → 𝐹 = 𝐹 ) | |
| 2 | id | ⊢ ( 𝐴 = 𝐵 → 𝐴 = 𝐵 ) | |
| 3 | 1 2 | afv2eq12d | ⊢ ( 𝐴 = 𝐵 → ( 𝐹 '''' 𝐴 ) = ( 𝐹 '''' 𝐵 ) ) |