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| Mirrors > Home > MPE Home > Th. List > df-symdif | Structured version Visualization version GIF version | ||
| Description: Define the symmetric difference of two classes. Alternate definitions are dfsymdif2 4227, dfsymdif3 4272 and dfsymdif4 4225. (Contributed by Scott Fenton, 31-Mar-2012.) |
| Ref | Expression |
|---|---|
| df-symdif | ⊢ (𝐴 △ 𝐵) = ((𝐴 ∖ 𝐵) ∪ (𝐵 ∖ 𝐴)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cA | . . 3 class 𝐴 | |
| 2 | cB | . . 3 class 𝐵 | |
| 3 | 1, 2 | csymdif 4218 | . 2 class (𝐴 △ 𝐵) |
| 4 | 1, 2 | cdif 3914 | . . 3 class (𝐴 ∖ 𝐵) |
| 5 | 2, 1 | cdif 3914 | . . 3 class (𝐵 ∖ 𝐴) |
| 6 | 4, 5 | cun 3915 | . 2 class ((𝐴 ∖ 𝐵) ∪ (𝐵 ∖ 𝐴)) |
| 7 | 3, 6 | wceq 1540 | 1 wff (𝐴 △ 𝐵) = ((𝐴 ∖ 𝐵) ∪ (𝐵 ∖ 𝐴)) |
| Colors of variables: wff setvar class |
| This definition is referenced by: symdifcom 4220 symdifeq1 4221 nfsymdif 4223 elsymdif 4224 difsssymdif 4229 dfsymdif3 4272 symdif0 5052 symdifv 5053 symdifid 5054 |
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