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Description: A utility lemma to transfer a bound-variable hypothesis builder into a definition. See hbxfreq for equality version. (Contributed by Jonathan Ben-Naim, 3-Jun-2011)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | hbxfrbi.1 | ⊢ ( 𝜑 ↔ 𝜓 ) | |
| hbxfrbi.2 | ⊢ ( 𝜓 → ∀ 𝑥 𝜓 ) | ||
| Assertion | hbxfrbi | ⊢ ( 𝜑 → ∀ 𝑥 𝜑 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hbxfrbi.1 | ⊢ ( 𝜑 ↔ 𝜓 ) | |
| 2 | hbxfrbi.2 | ⊢ ( 𝜓 → ∀ 𝑥 𝜓 ) | |
| 3 | 1 | albii | ⊢ ( ∀ 𝑥 𝜑 ↔ ∀ 𝑥 𝜓 ) |
| 4 | 2 1 3 | 3imtr4i | ⊢ ( 𝜑 → ∀ 𝑥 𝜑 ) |