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Mirrors > Home > MPE Home > Th. List > nrexrmo | Structured version Visualization version GIF version |
Description: Nonexistence implies restricted "at most one". (Contributed by NM, 17-Jun-2017.) |
Ref | Expression |
---|---|
nrexrmo | ⊢ (¬ ∃𝑥 ∈ 𝐴 𝜑 → ∃*𝑥 ∈ 𝐴 𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm2.21 120 | . 2 ⊢ (¬ ∃𝑥 ∈ 𝐴 𝜑 → (∃𝑥 ∈ 𝐴 𝜑 → ∃!𝑥 ∈ 𝐴 𝜑)) | |
2 | rmo5 3162 | . 2 ⊢ (∃*𝑥 ∈ 𝐴 𝜑 ↔ (∃𝑥 ∈ 𝐴 𝜑 → ∃!𝑥 ∈ 𝐴 𝜑)) | |
3 | 1, 2 | sylibr 224 | 1 ⊢ (¬ ∃𝑥 ∈ 𝐴 𝜑 → ∃*𝑥 ∈ 𝐴 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∃wrex 2913 ∃!wreu 2914 ∃*wrmo 2915 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 |
This theorem depends on definitions: df-bi 197 df-mo 2475 df-rex 2918 df-reu 2919 df-rmo 2920 |
This theorem is referenced by: (None) |
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