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Type | Label | Description |
---|---|---|
Statement | ||
Theorem | neqned 2801 | If it is not the case that two classes are equal, they are unequal. Converse of neneqd 2799. One-way deduction form of df-ne 2795. (Contributed by David Moews, 28-Feb-2017.) Allow a shortening of necon3bi 2820. (Revised by Wolf Lammen, 22-Nov-2019.) |
⊢ (𝜑 → ¬ 𝐴 = 𝐵) ⇒ ⊢ (𝜑 → 𝐴 ≠ 𝐵) | ||
Theorem | neqne 2802 | From non equality to inequality. (Contributed by Glauco Siliprandi, 11-Dec-2019.) |
⊢ (¬ 𝐴 = 𝐵 → 𝐴 ≠ 𝐵) | ||
Theorem | neirr 2803 | No class is unequal to itself. Inequality is irreflexive. (Contributed by Stefan O'Rear, 1-Jan-2015.) |
⊢ ¬ 𝐴 ≠ 𝐴 | ||
Theorem | exmidne 2804 | Excluded middle with equality and inequality. (Contributed by NM, 3-Feb-2012.) (Proof shortened by Wolf Lammen, 17-Nov-2019.) |
⊢ (𝐴 = 𝐵 ∨ 𝐴 ≠ 𝐵) | ||
Theorem | eqneqall 2805 | A contradiction concerning equality implies anything. (Contributed by Alexander van der Vekens, 25-Jan-2018.) |
⊢ (𝐴 = 𝐵 → (𝐴 ≠ 𝐵 → 𝜑)) | ||
Theorem | nonconne 2806 | Law of noncontradiction with equality and inequality. (Contributed by NM, 3-Feb-2012.) (Proof shortened by Wolf Lammen, 21-Dec-2019.) |
⊢ ¬ (𝐴 = 𝐵 ∧ 𝐴 ≠ 𝐵) | ||
Theorem | necon3ad 2807 | Contrapositive law deduction for inequality. (Contributed by NM, 2-Apr-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 23-Nov-2019.) |
⊢ (𝜑 → (𝜓 → 𝐴 = 𝐵)) ⇒ ⊢ (𝜑 → (𝐴 ≠ 𝐵 → ¬ 𝜓)) | ||
Theorem | necon3bd 2808 | Contrapositive law deduction for inequality. (Contributed by NM, 2-Apr-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) |
⊢ (𝜑 → (𝐴 = 𝐵 → 𝜓)) ⇒ ⊢ (𝜑 → (¬ 𝜓 → 𝐴 ≠ 𝐵)) | ||
Theorem | necon2ad 2809 | Contrapositive inference for inequality. (Contributed by NM, 19-Apr-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 23-Nov-2019.) |
⊢ (𝜑 → (𝐴 = 𝐵 → ¬ 𝜓)) ⇒ ⊢ (𝜑 → (𝜓 → 𝐴 ≠ 𝐵)) | ||
Theorem | necon2bd 2810 | Contrapositive inference for inequality. (Contributed by NM, 13-Apr-2007.) |
⊢ (𝜑 → (𝜓 → 𝐴 ≠ 𝐵)) ⇒ ⊢ (𝜑 → (𝐴 = 𝐵 → ¬ 𝜓)) | ||
Theorem | necon1ad 2811 | Contrapositive deduction for inequality. (Contributed by NM, 2-Apr-2007.) (Proof shortened by Wolf Lammen, 23-Nov-2019.) |
⊢ (𝜑 → (¬ 𝜓 → 𝐴 = 𝐵)) ⇒ ⊢ (𝜑 → (𝐴 ≠ 𝐵 → 𝜓)) | ||
Theorem | necon1bd 2812 | Contrapositive deduction for inequality. (Contributed by NM, 21-Mar-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 23-Nov-2019.) |
⊢ (𝜑 → (𝐴 ≠ 𝐵 → 𝜓)) ⇒ ⊢ (𝜑 → (¬ 𝜓 → 𝐴 = 𝐵)) | ||
Theorem | necon4ad 2813 | Contrapositive inference for inequality. (Contributed by NM, 2-Apr-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 23-Nov-2019.) |
⊢ (𝜑 → (𝐴 ≠ 𝐵 → ¬ 𝜓)) ⇒ ⊢ (𝜑 → (𝜓 → 𝐴 = 𝐵)) | ||
Theorem | necon4bd 2814 | Contrapositive inference for inequality. (Contributed by NM, 1-Jun-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 23-Nov-2019.) |
⊢ (𝜑 → (¬ 𝜓 → 𝐴 ≠ 𝐵)) ⇒ ⊢ (𝜑 → (𝐴 = 𝐵 → 𝜓)) | ||
Theorem | necon3d 2815 | Contrapositive law deduction for inequality. (Contributed by NM, 10-Jun-2006.) |
⊢ (𝜑 → (𝐴 = 𝐵 → 𝐶 = 𝐷)) ⇒ ⊢ (𝜑 → (𝐶 ≠ 𝐷 → 𝐴 ≠ 𝐵)) | ||
Theorem | necon1d 2816 | Contrapositive law deduction for inequality. (Contributed by NM, 28-Dec-2008.) (Proof shortened by Andrew Salmon, 25-May-2011.) |
⊢ (𝜑 → (𝐴 ≠ 𝐵 → 𝐶 = 𝐷)) ⇒ ⊢ (𝜑 → (𝐶 ≠ 𝐷 → 𝐴 = 𝐵)) | ||
Theorem | necon2d 2817 | Contrapositive inference for inequality. (Contributed by NM, 28-Dec-2008.) |
⊢ (𝜑 → (𝐴 = 𝐵 → 𝐶 ≠ 𝐷)) ⇒ ⊢ (𝜑 → (𝐶 = 𝐷 → 𝐴 ≠ 𝐵)) | ||
Theorem | necon4d 2818 | Contrapositive inference for inequality. (Contributed by NM, 2-Apr-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) |
⊢ (𝜑 → (𝐴 ≠ 𝐵 → 𝐶 ≠ 𝐷)) ⇒ ⊢ (𝜑 → (𝐶 = 𝐷 → 𝐴 = 𝐵)) | ||
Theorem | necon3ai 2819 | Contrapositive inference for inequality. (Contributed by NM, 23-May-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) |
⊢ (𝜑 → 𝐴 = 𝐵) ⇒ ⊢ (𝐴 ≠ 𝐵 → ¬ 𝜑) | ||
Theorem | necon3bi 2820 | Contrapositive inference for inequality. (Contributed by NM, 1-Jun-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 22-Nov-2019.) |
⊢ (𝐴 = 𝐵 → 𝜑) ⇒ ⊢ (¬ 𝜑 → 𝐴 ≠ 𝐵) | ||
Theorem | necon1ai 2821 | Contrapositive inference for inequality. (Contributed by NM, 12-Feb-2007.) (Proof shortened by Wolf Lammen, 22-Nov-2019.) |
⊢ (¬ 𝜑 → 𝐴 = 𝐵) ⇒ ⊢ (𝐴 ≠ 𝐵 → 𝜑) | ||
Theorem | necon1bi 2822 | Contrapositive inference for inequality. (Contributed by NM, 18-Mar-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 22-Nov-2019.) |
⊢ (𝐴 ≠ 𝐵 → 𝜑) ⇒ ⊢ (¬ 𝜑 → 𝐴 = 𝐵) | ||
Theorem | necon2ai 2823 | Contrapositive inference for inequality. (Contributed by NM, 16-Jan-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 22-Nov-2019.) |
⊢ (𝐴 = 𝐵 → ¬ 𝜑) ⇒ ⊢ (𝜑 → 𝐴 ≠ 𝐵) | ||
Theorem | necon2bi 2824 | Contrapositive inference for inequality. (Contributed by NM, 1-Apr-2007.) |
⊢ (𝜑 → 𝐴 ≠ 𝐵) ⇒ ⊢ (𝐴 = 𝐵 → ¬ 𝜑) | ||
Theorem | necon4ai 2825 | Contrapositive inference for inequality. (Contributed by NM, 16-Jan-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 22-Nov-2019.) |
⊢ (𝐴 ≠ 𝐵 → ¬ 𝜑) ⇒ ⊢ (𝜑 → 𝐴 = 𝐵) | ||
Theorem | necon3i 2826 | Contrapositive inference for inequality. (Contributed by NM, 9-Aug-2006.) (Proof shortened by Wolf Lammen, 22-Nov-2019.) |
⊢ (𝐴 = 𝐵 → 𝐶 = 𝐷) ⇒ ⊢ (𝐶 ≠ 𝐷 → 𝐴 ≠ 𝐵) | ||
Theorem | necon1i 2827 | Contrapositive inference for inequality. (Contributed by NM, 18-Mar-2007.) |
⊢ (𝐴 ≠ 𝐵 → 𝐶 = 𝐷) ⇒ ⊢ (𝐶 ≠ 𝐷 → 𝐴 = 𝐵) | ||
Theorem | necon2i 2828 | Contrapositive inference for inequality. (Contributed by NM, 18-Mar-2007.) |
⊢ (𝐴 = 𝐵 → 𝐶 ≠ 𝐷) ⇒ ⊢ (𝐶 = 𝐷 → 𝐴 ≠ 𝐵) | ||
Theorem | necon4i 2829 | Contrapositive inference for inequality. (Contributed by NM, 17-Mar-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 24-Nov-2019.) |
⊢ (𝐴 ≠ 𝐵 → 𝐶 ≠ 𝐷) ⇒ ⊢ (𝐶 = 𝐷 → 𝐴 = 𝐵) | ||
Theorem | necon3abid 2830 | Deduction from equality to inequality. (Contributed by NM, 21-Mar-2007.) |
⊢ (𝜑 → (𝐴 = 𝐵 ↔ 𝜓)) ⇒ ⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ ¬ 𝜓)) | ||
Theorem | necon3bbid 2831 | Deduction from equality to inequality. (Contributed by NM, 2-Jun-2007.) |
⊢ (𝜑 → (𝜓 ↔ 𝐴 = 𝐵)) ⇒ ⊢ (𝜑 → (¬ 𝜓 ↔ 𝐴 ≠ 𝐵)) | ||
Theorem | necon1abid 2832 | Contrapositive deduction for inequality. (Contributed by NM, 21-Aug-2007.) (Proof shortened by Wolf Lammen, 24-Nov-2019.) |
⊢ (𝜑 → (¬ 𝜓 ↔ 𝐴 = 𝐵)) ⇒ ⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ 𝜓)) | ||
Theorem | necon1bbid 2833 | Contrapositive inference for inequality. (Contributed by NM, 31-Jan-2008.) |
⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ 𝜓)) ⇒ ⊢ (𝜑 → (¬ 𝜓 ↔ 𝐴 = 𝐵)) | ||
Theorem | necon4abid 2834 | Contrapositive law deduction for inequality. (Contributed by NM, 11-Jan-2008.) (Proof shortened by Wolf Lammen, 24-Nov-2019.) |
⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ ¬ 𝜓)) ⇒ ⊢ (𝜑 → (𝐴 = 𝐵 ↔ 𝜓)) | ||
Theorem | necon4bbid 2835 | Contrapositive law deduction for inequality. (Contributed by NM, 9-May-2012.) |
⊢ (𝜑 → (¬ 𝜓 ↔ 𝐴 ≠ 𝐵)) ⇒ ⊢ (𝜑 → (𝜓 ↔ 𝐴 = 𝐵)) | ||
Theorem | necon2abid 2836 | Contrapositive deduction for inequality. (Contributed by NM, 18-Jul-2007.) (Proof shortened by Wolf Lammen, 24-Nov-2019.) |
⊢ (𝜑 → (𝐴 = 𝐵 ↔ ¬ 𝜓)) ⇒ ⊢ (𝜑 → (𝜓 ↔ 𝐴 ≠ 𝐵)) | ||
Theorem | necon2bbid 2837 | Contrapositive deduction for inequality. (Contributed by NM, 13-Apr-2007.) (Proof shortened by Wolf Lammen, 24-Nov-2019.) |
⊢ (𝜑 → (𝜓 ↔ 𝐴 ≠ 𝐵)) ⇒ ⊢ (𝜑 → (𝐴 = 𝐵 ↔ ¬ 𝜓)) | ||
Theorem | necon3bid 2838 | Deduction from equality to inequality. (Contributed by NM, 23-Feb-2005.) (Proof shortened by Andrew Salmon, 25-May-2011.) |
⊢ (𝜑 → (𝐴 = 𝐵 ↔ 𝐶 = 𝐷)) ⇒ ⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ 𝐶 ≠ 𝐷)) | ||
Theorem | necon4bid 2839 | Contrapositive law deduction for inequality. (Contributed by NM, 29-Jun-2007.) |
⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ 𝐶 ≠ 𝐷)) ⇒ ⊢ (𝜑 → (𝐴 = 𝐵 ↔ 𝐶 = 𝐷)) | ||
Theorem | necon3abii 2840 | Deduction from equality to inequality. (Contributed by NM, 9-Nov-2007.) |
⊢ (𝐴 = 𝐵 ↔ 𝜑) ⇒ ⊢ (𝐴 ≠ 𝐵 ↔ ¬ 𝜑) | ||
Theorem | necon3bbii 2841 | Deduction from equality to inequality. (Contributed by NM, 13-Apr-2007.) |
⊢ (𝜑 ↔ 𝐴 = 𝐵) ⇒ ⊢ (¬ 𝜑 ↔ 𝐴 ≠ 𝐵) | ||
Theorem | necon1abii 2842 | Contrapositive inference for inequality. (Contributed by NM, 17-Mar-2007.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ (¬ 𝜑 ↔ 𝐴 = 𝐵) ⇒ ⊢ (𝐴 ≠ 𝐵 ↔ 𝜑) | ||
Theorem | necon1bbii 2843 | Contrapositive inference for inequality. (Contributed by NM, 17-Mar-2007.) (Proof shortened by Wolf Lammen, 24-Nov-2019.) |
⊢ (𝐴 ≠ 𝐵 ↔ 𝜑) ⇒ ⊢ (¬ 𝜑 ↔ 𝐴 = 𝐵) | ||
Theorem | necon2abii 2844 | Contrapositive inference for inequality. (Contributed by NM, 2-Mar-2007.) |
⊢ (𝐴 = 𝐵 ↔ ¬ 𝜑) ⇒ ⊢ (𝜑 ↔ 𝐴 ≠ 𝐵) | ||
Theorem | necon2bbii 2845 | Contrapositive inference for inequality. (Contributed by NM, 13-Apr-2007.) |
⊢ (𝜑 ↔ 𝐴 ≠ 𝐵) ⇒ ⊢ (𝐴 = 𝐵 ↔ ¬ 𝜑) | ||
Theorem | necon3bii 2846 | Inference from equality to inequality. (Contributed by NM, 23-Feb-2005.) |
⊢ (𝐴 = 𝐵 ↔ 𝐶 = 𝐷) ⇒ ⊢ (𝐴 ≠ 𝐵 ↔ 𝐶 ≠ 𝐷) | ||
Theorem | necom 2847 | Commutation of inequality. (Contributed by NM, 14-May-1999.) |
⊢ (𝐴 ≠ 𝐵 ↔ 𝐵 ≠ 𝐴) | ||
Theorem | necomi 2848 | Inference from commutative law for inequality. (Contributed by NM, 17-Oct-2012.) |
⊢ 𝐴 ≠ 𝐵 ⇒ ⊢ 𝐵 ≠ 𝐴 | ||
Theorem | necomd 2849 | Deduction from commutative law for inequality. (Contributed by NM, 12-Feb-2008.) |
⊢ (𝜑 → 𝐴 ≠ 𝐵) ⇒ ⊢ (𝜑 → 𝐵 ≠ 𝐴) | ||
Theorem | nesym 2850 | Characterization of inequality in terms of reversed equality (see bicom 212). (Contributed by BJ, 7-Jul-2018.) |
⊢ (𝐴 ≠ 𝐵 ↔ ¬ 𝐵 = 𝐴) | ||
Theorem | nesymi 2851 | Inference associated with nesym 2850. (Contributed by BJ, 7-Jul-2018.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ 𝐴 ≠ 𝐵 ⇒ ⊢ ¬ 𝐵 = 𝐴 | ||
Theorem | nesymir 2852 | Inference associated with nesym 2850. (Contributed by BJ, 7-Jul-2018.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ ¬ 𝐴 = 𝐵 ⇒ ⊢ 𝐵 ≠ 𝐴 | ||
Theorem | neeq1d 2853 | Deduction for inequality. (Contributed by NM, 25-Oct-1999.) (Proof shortened by Wolf Lammen, 19-Nov-2019.) |
⊢ (𝜑 → 𝐴 = 𝐵) ⇒ ⊢ (𝜑 → (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐶)) | ||
Theorem | neeq2d 2854 | Deduction for inequality. (Contributed by NM, 25-Oct-1999.) (Proof shortened by Wolf Lammen, 19-Nov-2019.) |
⊢ (𝜑 → 𝐴 = 𝐵) ⇒ ⊢ (𝜑 → (𝐶 ≠ 𝐴 ↔ 𝐶 ≠ 𝐵)) | ||
Theorem | neeq12d 2855 | Deduction for inequality. (Contributed by NM, 24-Jul-2012.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ (𝜑 → 𝐴 = 𝐵) & ⊢ (𝜑 → 𝐶 = 𝐷) ⇒ ⊢ (𝜑 → (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐷)) | ||
Theorem | neeq1 2856 | Equality theorem for inequality. (Contributed by NM, 19-Nov-1994.) (Proof shortened by Wolf Lammen, 18-Nov-2019.) |
⊢ (𝐴 = 𝐵 → (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐶)) | ||
Theorem | neeq2 2857 | Equality theorem for inequality. (Contributed by NM, 19-Nov-1994.) (Proof shortened by Wolf Lammen, 18-Nov-2019.) |
⊢ (𝐴 = 𝐵 → (𝐶 ≠ 𝐴 ↔ 𝐶 ≠ 𝐵)) | ||
Theorem | neeq1i 2858 | Inference for inequality. (Contributed by NM, 29-Apr-2005.) (Proof shortened by Wolf Lammen, 19-Nov-2019.) |
⊢ 𝐴 = 𝐵 ⇒ ⊢ (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐶) | ||
Theorem | neeq2i 2859 | Inference for inequality. (Contributed by NM, 29-Apr-2005.) (Proof shortened by Wolf Lammen, 19-Nov-2019.) |
⊢ 𝐴 = 𝐵 ⇒ ⊢ (𝐶 ≠ 𝐴 ↔ 𝐶 ≠ 𝐵) | ||
Theorem | neeq12i 2860 | Inference for inequality. (Contributed by NM, 24-Jul-2012.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ 𝐴 = 𝐵 & ⊢ 𝐶 = 𝐷 ⇒ ⊢ (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐷) | ||
Theorem | eqnetrd 2861 | Substitution of equal classes into an inequality. (Contributed by NM, 4-Jul-2012.) |
⊢ (𝜑 → 𝐴 = 𝐵) & ⊢ (𝜑 → 𝐵 ≠ 𝐶) ⇒ ⊢ (𝜑 → 𝐴 ≠ 𝐶) | ||
Theorem | eqnetrrd 2862 | Substitution of equal classes into an inequality. (Contributed by NM, 4-Jul-2012.) |
⊢ (𝜑 → 𝐴 = 𝐵) & ⊢ (𝜑 → 𝐴 ≠ 𝐶) ⇒ ⊢ (𝜑 → 𝐵 ≠ 𝐶) | ||
Theorem | neeqtrd 2863 | Substitution of equal classes into an inequality. (Contributed by NM, 4-Jul-2012.) |
⊢ (𝜑 → 𝐴 ≠ 𝐵) & ⊢ (𝜑 → 𝐵 = 𝐶) ⇒ ⊢ (𝜑 → 𝐴 ≠ 𝐶) | ||
Theorem | eqnetri 2864 | Substitution of equal classes into an inequality. (Contributed by NM, 4-Jul-2012.) |
⊢ 𝐴 = 𝐵 & ⊢ 𝐵 ≠ 𝐶 ⇒ ⊢ 𝐴 ≠ 𝐶 | ||
Theorem | eqnetrri 2865 | Substitution of equal classes into an inequality. (Contributed by NM, 4-Jul-2012.) |
⊢ 𝐴 = 𝐵 & ⊢ 𝐴 ≠ 𝐶 ⇒ ⊢ 𝐵 ≠ 𝐶 | ||
Theorem | neeqtri 2866 | Substitution of equal classes into an inequality. (Contributed by NM, 4-Jul-2012.) |
⊢ 𝐴 ≠ 𝐵 & ⊢ 𝐵 = 𝐶 ⇒ ⊢ 𝐴 ≠ 𝐶 | ||
Theorem | neeqtrri 2867 | Substitution of equal classes into an inequality. (Contributed by NM, 4-Jul-2012.) |
⊢ 𝐴 ≠ 𝐵 & ⊢ 𝐶 = 𝐵 ⇒ ⊢ 𝐴 ≠ 𝐶 | ||
Theorem | neeqtrrd 2868 | Substitution of equal classes into an inequality. (Contributed by NM, 4-Jul-2012.) |
⊢ (𝜑 → 𝐴 ≠ 𝐵) & ⊢ (𝜑 → 𝐶 = 𝐵) ⇒ ⊢ (𝜑 → 𝐴 ≠ 𝐶) | ||
Theorem | syl5eqner 2869 | A chained equality inference for inequality. (Contributed by NM, 6-Jun-2012.) (Proof shortened by Wolf Lammen, 19-Nov-2019.) |
⊢ 𝐵 = 𝐴 & ⊢ (𝜑 → 𝐵 ≠ 𝐶) ⇒ ⊢ (𝜑 → 𝐴 ≠ 𝐶) | ||
Theorem | 3netr3d 2870 | Substitution of equality into both sides of an inequality. (Contributed by NM, 24-Jul-2012.) (Proof shortened by Wolf Lammen, 19-Nov-2019.) |
⊢ (𝜑 → 𝐴 ≠ 𝐵) & ⊢ (𝜑 → 𝐴 = 𝐶) & ⊢ (𝜑 → 𝐵 = 𝐷) ⇒ ⊢ (𝜑 → 𝐶 ≠ 𝐷) | ||
Theorem | 3netr4d 2871 | Substitution of equality into both sides of an inequality. (Contributed by NM, 24-Jul-2012.) (Proof shortened by Wolf Lammen, 21-Nov-2019.) |
⊢ (𝜑 → 𝐴 ≠ 𝐵) & ⊢ (𝜑 → 𝐶 = 𝐴) & ⊢ (𝜑 → 𝐷 = 𝐵) ⇒ ⊢ (𝜑 → 𝐶 ≠ 𝐷) | ||
Theorem | 3netr3g 2872 | Substitution of equality into both sides of an inequality. (Contributed by NM, 24-Jul-2012.) |
⊢ (𝜑 → 𝐴 ≠ 𝐵) & ⊢ 𝐴 = 𝐶 & ⊢ 𝐵 = 𝐷 ⇒ ⊢ (𝜑 → 𝐶 ≠ 𝐷) | ||
Theorem | 3netr4g 2873 | Substitution of equality into both sides of an inequality. (Contributed by NM, 14-Jun-2012.) |
⊢ (𝜑 → 𝐴 ≠ 𝐵) & ⊢ 𝐶 = 𝐴 & ⊢ 𝐷 = 𝐵 ⇒ ⊢ (𝜑 → 𝐶 ≠ 𝐷) | ||
Theorem | nebi 2874 | Contraposition law for inequality. (Contributed by NM, 28-Dec-2008.) |
⊢ ((𝐴 = 𝐵 ↔ 𝐶 = 𝐷) ↔ (𝐴 ≠ 𝐵 ↔ 𝐶 ≠ 𝐷)) | ||
Theorem | pm13.18 2875 | Theorem *13.18 in [WhiteheadRussell] p. 178. (Contributed by Andrew Salmon, 3-Jun-2011.) |
⊢ ((𝐴 = 𝐵 ∧ 𝐴 ≠ 𝐶) → 𝐵 ≠ 𝐶) | ||
Theorem | pm13.181 2876 | Theorem *13.181 in [WhiteheadRussell] p. 178. (Contributed by Andrew Salmon, 3-Jun-2011.) |
⊢ ((𝐴 = 𝐵 ∧ 𝐵 ≠ 𝐶) → 𝐴 ≠ 𝐶) | ||
Theorem | pm2.61ine 2877 | Inference eliminating an inequality in an antecedent. (Contributed by NM, 16-Jan-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) |
⊢ (𝐴 = 𝐵 → 𝜑) & ⊢ (𝐴 ≠ 𝐵 → 𝜑) ⇒ ⊢ 𝜑 | ||
Theorem | pm2.21ddne 2878 | A contradiction implies anything. Equality/inequality deduction form. (Contributed by David Moews, 28-Feb-2017.) |
⊢ (𝜑 → 𝐴 = 𝐵) & ⊢ (𝜑 → 𝐴 ≠ 𝐵) ⇒ ⊢ (𝜑 → 𝜓) | ||
Theorem | pm2.61ne 2879 | Deduction eliminating an inequality in an antecedent. (Contributed by NM, 24-May-2006.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ (𝐴 = 𝐵 → (𝜓 ↔ 𝜒)) & ⊢ ((𝜑 ∧ 𝐴 ≠ 𝐵) → 𝜓) & ⊢ (𝜑 → 𝜒) ⇒ ⊢ (𝜑 → 𝜓) | ||
Theorem | pm2.61dne 2880 | Deduction eliminating an inequality in an antecedent. (Contributed by NM, 1-Jun-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) |
⊢ (𝜑 → (𝐴 = 𝐵 → 𝜓)) & ⊢ (𝜑 → (𝐴 ≠ 𝐵 → 𝜓)) ⇒ ⊢ (𝜑 → 𝜓) | ||
Theorem | pm2.61dane 2881 | Deduction eliminating an inequality in an antecedent. (Contributed by NM, 30-Nov-2011.) |
⊢ ((𝜑 ∧ 𝐴 = 𝐵) → 𝜓) & ⊢ ((𝜑 ∧ 𝐴 ≠ 𝐵) → 𝜓) ⇒ ⊢ (𝜑 → 𝜓) | ||
Theorem | pm2.61da2ne 2882 | Deduction eliminating two inequalities in an antecedent. (Contributed by NM, 29-May-2013.) |
⊢ ((𝜑 ∧ 𝐴 = 𝐵) → 𝜓) & ⊢ ((𝜑 ∧ 𝐶 = 𝐷) → 𝜓) & ⊢ ((𝜑 ∧ (𝐴 ≠ 𝐵 ∧ 𝐶 ≠ 𝐷)) → 𝜓) ⇒ ⊢ (𝜑 → 𝜓) | ||
Theorem | pm2.61da3ne 2883 | Deduction eliminating three inequalities in an antecedent. (Contributed by NM, 15-Jun-2013.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ ((𝜑 ∧ 𝐴 = 𝐵) → 𝜓) & ⊢ ((𝜑 ∧ 𝐶 = 𝐷) → 𝜓) & ⊢ ((𝜑 ∧ 𝐸 = 𝐹) → 𝜓) & ⊢ ((𝜑 ∧ (𝐴 ≠ 𝐵 ∧ 𝐶 ≠ 𝐷 ∧ 𝐸 ≠ 𝐹)) → 𝜓) ⇒ ⊢ (𝜑 → 𝜓) | ||
Theorem | pm2.61iine 2884 | Equality version of pm2.61ii 177. (Contributed by Scott Fenton, 13-Jun-2013.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ ((𝐴 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷) → 𝜑) & ⊢ (𝐴 = 𝐶 → 𝜑) & ⊢ (𝐵 = 𝐷 → 𝜑) ⇒ ⊢ 𝜑 | ||
Theorem | neor 2885 | Logical OR with an equality. (Contributed by NM, 29-Apr-2007.) |
⊢ ((𝐴 = 𝐵 ∨ 𝜓) ↔ (𝐴 ≠ 𝐵 → 𝜓)) | ||
Theorem | neanior 2886 | A De Morgan's law for inequality. (Contributed by NM, 18-May-2007.) |
⊢ ((𝐴 ≠ 𝐵 ∧ 𝐶 ≠ 𝐷) ↔ ¬ (𝐴 = 𝐵 ∨ 𝐶 = 𝐷)) | ||
Theorem | ne3anior 2887 | A De Morgan's law for inequality. (Contributed by NM, 30-Sep-2013.) |
⊢ ((𝐴 ≠ 𝐵 ∧ 𝐶 ≠ 𝐷 ∧ 𝐸 ≠ 𝐹) ↔ ¬ (𝐴 = 𝐵 ∨ 𝐶 = 𝐷 ∨ 𝐸 = 𝐹)) | ||
Theorem | neorian 2888 | A De Morgan's law for inequality. (Contributed by NM, 18-May-2007.) |
⊢ ((𝐴 ≠ 𝐵 ∨ 𝐶 ≠ 𝐷) ↔ ¬ (𝐴 = 𝐵 ∧ 𝐶 = 𝐷)) | ||
Theorem | nemtbir 2889 | An inference from an inequality, related to modus tollens. (Contributed by NM, 13-Apr-2007.) |
⊢ 𝐴 ≠ 𝐵 & ⊢ (𝜑 ↔ 𝐴 = 𝐵) ⇒ ⊢ ¬ 𝜑 | ||
Theorem | nelne1 2890 | Two classes are different if they don't contain the same element. (Contributed by NM, 3-Feb-2012.) |
⊢ ((𝐴 ∈ 𝐵 ∧ ¬ 𝐴 ∈ 𝐶) → 𝐵 ≠ 𝐶) | ||
Theorem | nelne2 2891 | Two classes are different if they don't belong to the same class. (Contributed by NM, 25-Jun-2012.) |
⊢ ((𝐴 ∈ 𝐶 ∧ ¬ 𝐵 ∈ 𝐶) → 𝐴 ≠ 𝐵) | ||
Theorem | nelelne 2892 | Two classes are different if they don't belong to the same class. (Contributed by Rodolfo Medina, 17-Oct-2010.) (Proof shortened by AV, 10-May-2020.) |
⊢ (¬ 𝐴 ∈ 𝐵 → (𝐶 ∈ 𝐵 → 𝐶 ≠ 𝐴)) | ||
Theorem | neneor 2893 | If two classes are different, a third class must be different of at least one of them. (Contributed by Thierry Arnoux, 8-Aug-2020.) |
⊢ (𝐴 ≠ 𝐵 → (𝐴 ≠ 𝐶 ∨ 𝐵 ≠ 𝐶)) | ||
Theorem | nfne 2894 | Bound-variable hypothesis builder for inequality. (Contributed by NM, 10-Nov-2007.) (Revised by Mario Carneiro, 7-Oct-2016.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑥𝐵 ⇒ ⊢ Ⅎ𝑥 𝐴 ≠ 𝐵 | ||
Theorem | nfned 2895 | Bound-variable hypothesis builder for inequality. (Contributed by NM, 10-Nov-2007.) (Revised by Mario Carneiro, 7-Oct-2016.) |
⊢ (𝜑 → Ⅎ𝑥𝐴) & ⊢ (𝜑 → Ⅎ𝑥𝐵) ⇒ ⊢ (𝜑 → Ⅎ𝑥 𝐴 ≠ 𝐵) | ||
Theorem | nabbi 2896 | Not equivalent wff's correspond to not equal class abstractions. (Contributed by AV, 7-Apr-2019.) (Proof shortened by Wolf Lammen, 25-Nov-2019.) |
⊢ (∃𝑥(𝜑 ↔ ¬ 𝜓) ↔ {𝑥 ∣ 𝜑} ≠ {𝑥 ∣ 𝜓}) | ||
Syntax | wnel 2897 | Extend wff notation to include negated membership. |
wff 𝐴 ∉ 𝐵 | ||
Definition | df-nel 2898 | Define negated membership. (Contributed by NM, 7-Aug-1994.) |
⊢ (𝐴 ∉ 𝐵 ↔ ¬ 𝐴 ∈ 𝐵) | ||
Theorem | neli 2899 | Inference associated with df-nel 2898. (Contributed by BJ, 7-Jul-2018.) |
⊢ 𝐴 ∉ 𝐵 ⇒ ⊢ ¬ 𝐴 ∈ 𝐵 | ||
Theorem | nelir 2900 | Inference associated with df-nel 2898. (Contributed by BJ, 7-Jul-2018.) |
⊢ ¬ 𝐴 ∈ 𝐵 ⇒ ⊢ 𝐴 ∉ 𝐵 |
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