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Description: General equality theorem for the well-ordered recursive function generator. (Contributed by Scott Fenton, 7-Jun-2018) (Proof shortened by Scott Fenton, 17-Nov-2024)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | wrecseq123 | ⊢ ( ( 𝑅 = 𝑆 ∧ 𝐴 = 𝐵 ∧ 𝐹 = 𝐺 ) → wrecs ( 𝑅 , 𝐴 , 𝐹 ) = wrecs ( 𝑆 , 𝐵 , 𝐺 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | coeq1 | ⊢ ( 𝐹 = 𝐺 → ( 𝐹 ∘ 2nd ) = ( 𝐺 ∘ 2nd ) ) | |
| 2 | frecseq123 | ⊢ ( ( 𝑅 = 𝑆 ∧ 𝐴 = 𝐵 ∧ ( 𝐹 ∘ 2nd ) = ( 𝐺 ∘ 2nd ) ) → frecs ( 𝑅 , 𝐴 , ( 𝐹 ∘ 2nd ) ) = frecs ( 𝑆 , 𝐵 , ( 𝐺 ∘ 2nd ) ) ) | |
| 3 | 1 2 | syl3an3 | ⊢ ( ( 𝑅 = 𝑆 ∧ 𝐴 = 𝐵 ∧ 𝐹 = 𝐺 ) → frecs ( 𝑅 , 𝐴 , ( 𝐹 ∘ 2nd ) ) = frecs ( 𝑆 , 𝐵 , ( 𝐺 ∘ 2nd ) ) ) |
| 4 | df-wrecs | ⊢ wrecs ( 𝑅 , 𝐴 , 𝐹 ) = frecs ( 𝑅 , 𝐴 , ( 𝐹 ∘ 2nd ) ) | |
| 5 | df-wrecs | ⊢ wrecs ( 𝑆 , 𝐵 , 𝐺 ) = frecs ( 𝑆 , 𝐵 , ( 𝐺 ∘ 2nd ) ) | |
| 6 | 3 4 5 | 3eqtr4g | ⊢ ( ( 𝑅 = 𝑆 ∧ 𝐴 = 𝐵 ∧ 𝐹 = 𝐺 ) → wrecs ( 𝑅 , 𝐴 , 𝐹 ) = wrecs ( 𝑆 , 𝐵 , 𝐺 ) ) |