where are relations between ``⊎, ×, ¬``

Please, where in lib-2.3 are implemented relations between ``⊎, ×, ¬`` ?
For example:
```
¬A→¬B→¬⊎ :  ∀ {α β} {A : Set α} {B : Set β} → ¬ A → ¬ B → ¬ (A ⊎ B)
```
