The complete lattice structure on UpperSet
/LowerSet
#
This file defines a completely distributive lattice structure on UpperSet
and LowerSet
,
pulled back across the canonical injection (UpperSet.carrier
, LowerSet.carrier
) into Set α
.
Notes #
Upper sets are ordered by reverse inclusion. This convention is motivated by the fact that this
makes them order-isomorphic to lower sets and antichains, and matches the convention on Filter
.
Equations
- UpperSet.instSetLike = { coe := UpperSet.carrier, coe_injective' := ⋯ }
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Equations
- LowerSet.instSetLike = { coe := LowerSet.carrier, coe_injective' := ⋯ }
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Equations
- UpperSet.completeLattice = Function.Injective.completeLattice (⇑OrderDual.toDual ∘ SetLike.coe) ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯
Equations
- One or more equations did not get rendered due to their size.
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Equations
Equations
- One or more equations did not get rendered due to their size.
Complement #
Upper sets are order-isomorphic to lower sets under complementation.
Equations
- upperSetIsoLowerSet = { toFun := UpperSet.compl, invFun := LowerSet.compl, left_inv := ⋯, right_inv := ⋯, map_rel_iff' := ⋯ }
Instances For
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noncomputable instance
UpperSet.instLinearOrder
{α : Type u_1}
[LinearOrder α]
:
LinearOrder (UpperSet α)
Equations
noncomputable instance
LowerSet.instLinearOrder
{α : Type u_1}
[LinearOrder α]
:
LinearOrder (LowerSet α)
Equations
Equations
- One or more equations did not get rendered due to their size.
Equations
- One or more equations did not get rendered due to their size.
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