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Description: Equality theorem for the choice set function. (Contributed by Mario Carneiro, 31-Aug-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | acneq | ⊢ ( 𝐴 = 𝐶 → AC 𝐴 = AC 𝐶 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eleq1 | ⊢ ( 𝐴 = 𝐶 → ( 𝐴 ∈ V ↔ 𝐶 ∈ V ) ) | |
| 2 | oveq2 | ⊢ ( 𝐴 = 𝐶 → ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐴 ) = ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐶 ) ) | |
| 3 | raleq | ⊢ ( 𝐴 = 𝐶 → ( ∀ 𝑦 ∈ 𝐴 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ↔ ∀ 𝑦 ∈ 𝐶 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) ) | |
| 4 | 3 | exbidv | ⊢ ( 𝐴 = 𝐶 → ( ∃ 𝑔 ∀ 𝑦 ∈ 𝐴 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ↔ ∃ 𝑔 ∀ 𝑦 ∈ 𝐶 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) ) |
| 5 | 2 4 | raleqbidv | ⊢ ( 𝐴 = 𝐶 → ( ∀ 𝑓 ∈ ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐴 ) ∃ 𝑔 ∀ 𝑦 ∈ 𝐴 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ↔ ∀ 𝑓 ∈ ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐶 ) ∃ 𝑔 ∀ 𝑦 ∈ 𝐶 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) ) |
| 6 | 1 5 | anbi12d | ⊢ ( 𝐴 = 𝐶 → ( ( 𝐴 ∈ V ∧ ∀ 𝑓 ∈ ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐴 ) ∃ 𝑔 ∀ 𝑦 ∈ 𝐴 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) ↔ ( 𝐶 ∈ V ∧ ∀ 𝑓 ∈ ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐶 ) ∃ 𝑔 ∀ 𝑦 ∈ 𝐶 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) ) ) |
| 7 | 6 | abbidv | ⊢ ( 𝐴 = 𝐶 → { 𝑥 ∣ ( 𝐴 ∈ V ∧ ∀ 𝑓 ∈ ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐴 ) ∃ 𝑔 ∀ 𝑦 ∈ 𝐴 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) } = { 𝑥 ∣ ( 𝐶 ∈ V ∧ ∀ 𝑓 ∈ ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐶 ) ∃ 𝑔 ∀ 𝑦 ∈ 𝐶 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) } ) |
| 8 | df-acn | ⊢ AC 𝐴 = { 𝑥 ∣ ( 𝐴 ∈ V ∧ ∀ 𝑓 ∈ ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐴 ) ∃ 𝑔 ∀ 𝑦 ∈ 𝐴 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) } | |
| 9 | df-acn | ⊢ AC 𝐶 = { 𝑥 ∣ ( 𝐶 ∈ V ∧ ∀ 𝑓 ∈ ( ( 𝒫 𝑥 ∖ { ∅ } ) ↑m 𝐶 ) ∃ 𝑔 ∀ 𝑦 ∈ 𝐶 ( 𝑔 ‘ 𝑦 ) ∈ ( 𝑓 ‘ 𝑦 ) ) } | |
| 10 | 7 8 9 | 3eqtr4g | ⊢ ( 𝐴 = 𝐶 → AC 𝐴 = AC 𝐶 ) |