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| Mirrors > Home > ILE Home > Th. List > Mathboxes > ralrals | GIF version | ||
| Description: If the universal part of a restricted "all some" statement holds, then the statement reduces to the existence of a member of 𝐴 satisfying its antecedent. This is the restricted counterpart of ralals 17063. (Contributed by Peter Mazsa and David A. Wheeler, 20-Jul-2026.) |
| Ref | Expression |
|---|---|
| ralrals | ⊢ (∀𝑥 ∈ 𝐴 (𝜑 → 𝜓) → (∀∃𝑥 ∈ 𝐴(𝜑 → 𝜓) ↔ ∃𝑥 ∈ 𝐴 𝜑)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-rals 17037 | . 2 ⊢ (∀∃𝑥 ∈ 𝐴(𝜑 → 𝜓) ↔ (∀𝑥 ∈ 𝐴 (𝜑 → 𝜓) ∧ ∃𝑥 ∈ 𝐴 𝜑)) | |
| 2 | ibar 301 | . . 3 ⊢ (∀𝑥 ∈ 𝐴 (𝜑 → 𝜓) → (∃𝑥 ∈ 𝐴 𝜑 ↔ (∀𝑥 ∈ 𝐴 (𝜑 → 𝜓) ∧ ∃𝑥 ∈ 𝐴 𝜑))) | |
| 3 | 2 | bicomd 141 | . 2 ⊢ (∀𝑥 ∈ 𝐴 (𝜑 → 𝜓) → ((∀𝑥 ∈ 𝐴 (𝜑 → 𝜓) ∧ ∃𝑥 ∈ 𝐴 𝜑) ↔ ∃𝑥 ∈ 𝐴 𝜑)) |
| 4 | 1, 3 | bitrid 192 | 1 ⊢ (∀𝑥 ∈ 𝐴 (𝜑 → 𝜓) → (∀∃𝑥 ∈ 𝐴(𝜑 → 𝜓) ↔ ∃𝑥 ∈ 𝐴 𝜑)) |
| Colors of variables: wff set class |
| Syntax hints: → wi 4 ∧ wa 104 ↔ wb 105 ∀wral 2528 ∃wrex 2529 ∀∃wrals 17035 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 |
| This theorem depends on definitions: df-bi 117 df-rals 17037 |
| This theorem is referenced by: (None) |
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