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[ deprecate ] names for deMorgan lemmas in Relation.Nullary.Negation #2838

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[ deprecate ] names for deMorgan lemmas in Relation.Nullary.Negation #2838

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9 changes: 9 additions & 0 deletions CHANGELOG.md
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Expand Up @@ -46,6 +46,15 @@ Deprecated names
interchange ↦ medial
```

* In `Relation.Nullary.Negation`:
```agda
∃⟶¬∀¬ ↦ ∃⇒¬∀¬
∀⟶¬∃¬ ↦ ∀⇒¬∃¬
¬∃⟶∀¬ ↦ ¬∃⇒∀¬
∀¬⟶¬∃ ↦ ∀¬⇒¬∃
∃¬⟶¬∀ ↦ ∃¬⇒¬∀
```

New modules
-----------

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59 changes: 49 additions & 10 deletions src/Relation/Nullary/Negation.agda
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Expand Up @@ -32,20 +32,20 @@ open import Relation.Nullary.Negation.Core public
------------------------------------------------------------------------
-- Quantifier juggling

∃⟶¬∀¬ : ∃ P → ¬ (∀ x → ¬ P x)
∃⟶¬∀¬ = flip uncurry
∃⇒¬∀¬ : ∃ P → ¬ (∀ x → ¬ P x)
∃⇒¬∀¬ = flip uncurry

∀⟶¬∃¬ : (∀ x → P x) → ¬ ∃ λ x → ¬ P x
∀⟶¬∃¬ ∀xPx (x , ¬Px) = ¬Px (∀xPx x)
∀⇒¬∃¬ : (∀ x → P x) → ¬ ∃ λ x → ¬ P x
∀⇒¬∃¬ ∀xPx (x , ¬Px) = ¬Px (∀xPx x)

¬∃⟶∀¬ : ¬ ∃ (λ x → P x) → ∀ x → ¬ P x
¬∃⟶∀¬ = curry
¬∃⇒∀¬ : ¬ ∃ (λ x → P x) → ∀ x → ¬ P x
¬∃⇒∀¬ = curry

∀¬⟶¬∃ : (∀ x → ¬ P x) → ¬ ∃ (λ x → P x)
∀¬⟶¬∃ = uncurry
∀¬⇒¬∃ : (∀ x → ¬ P x) → ¬ ∃ (λ x → P x)
∀¬⇒¬∃ = uncurry

∃¬⟶¬∀ : ∃ (λ x → ¬ P x) → ¬ (∀ x → P x)
∃¬⟶¬∀ = flip ∀⟶¬∃¬
∃¬⇒¬∀ : ∃ (λ x → ¬ P x) → ¬ (∀ x → P x)
∃¬⇒¬∀ = flip ∀⇒¬∃¬

------------------------------------------------------------------------
-- Double Negation
Expand Down Expand Up @@ -106,3 +106,42 @@ private
helper : ∃ (λ b → A → if b then B else C) → (A → B) ⊎ (A → C)
helper (true , f) = inj₁ f
helper (false , f) = inj₂ f


------------------------------------------------------------------------
-- DEPRECATED NAMES
------------------------------------------------------------------------
-- Please use the new names as continuing support for the old names is
-- not guaranteed.

-- Version 2.4

∃⟶¬∀¬ = ∃⇒¬∀¬
{-# WARNING_ON_USAGE ∃⟶¬∀¬
"Warning: ∃⟶¬∀¬ was deprecated in v2.4.
Please use ∃⇒¬∀¬ instead."
#-}

∀⟶¬∃¬ = ∀⇒¬∃¬
{-# WARNING_ON_USAGE ∀⟶¬∃¬
"Warning: ∀⟶¬∃¬ was deprecated in v2.4.
Please use ∀⇒¬∃¬ instead."
#-}

¬∃⟶∀¬ = ¬∃⇒∀¬
{-# WARNING_ON_USAGE ¬∃⟶∀¬
"Warning: ¬∃⟶∀¬ was deprecated in v2.4.
Please use ¬∃⇒∀¬ instead."
#-}

∀¬⟶¬∃ = ∀¬⇒¬∃
{-# WARNING_ON_USAGE ∀¬⟶¬∃
"Warning: ∀¬⟶¬∃ was deprecated in v2.4.
Please use ∀¬⇒¬∃ instead."
#-}

∃¬⟶¬∀ = ∃¬⇒¬∀
{-# WARNING_ON_USAGE ∃¬⟶¬∀
"Warning: ∃¬⟶¬∀ was deprecated in v2.4.
Please use ∃¬⇒¬∀ instead."
#-}