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Mirrors > Home > MPE Home > Th. List > nfeu | Structured version Visualization version GIF version |
Description: Bound-variable hypothesis builder for the unique existential quantifier. Note that 𝑥 and 𝑦 need not be disjoint. Usage of this theorem is discouraged because it depends on ax-13 2363. Use the weaker nfeuw 2579 when possible. (Contributed by NM, 8-Mar-1995.) (Revised by Mario Carneiro, 7-Oct-2016.) (New usage is discouraged.) |
Ref | Expression |
---|---|
nfeu.1 | ⊢ Ⅎ𝑥𝜑 |
Ref | Expression |
---|---|
nfeu | ⊢ Ⅎ𝑥∃!𝑦𝜑 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nftru 1798 | . . 3 ⊢ Ⅎ𝑦⊤ | |
2 | nfeu.1 | . . . 4 ⊢ Ⅎ𝑥𝜑 | |
3 | 2 | a1i 11 | . . 3 ⊢ (⊤ → Ⅎ𝑥𝜑) |
4 | 1, 3 | nfeud 2578 | . 2 ⊢ (⊤ → Ⅎ𝑥∃!𝑦𝜑) |
5 | 4 | mptru 1540 | 1 ⊢ Ⅎ𝑥∃!𝑦𝜑 |
Colors of variables: wff setvar class |
Syntax hints: ⊤wtru 1534 Ⅎwnf 1777 ∃!weu 2554 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-10 2129 ax-11 2146 ax-12 2163 ax-13 2363 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-tru 1536 df-ex 1774 df-nf 1778 df-mo 2526 df-eu 2555 |
This theorem is referenced by: 2eu7 2645 2eu8 2646 |
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