Lattice operations on finsets #
This file is concerned with folding binary lattice operations over finsets.
For the special case of maximum and minimum of a finset, see Max.lean.
See also Mathlib/Order/CompleteLattice/Finset.lean, which is instead concerned with how big
lattice or set operations behave when indexed by a finset.
sup #
Supremum of a finite set: sup {a, b, c} f = f a ⊔ f b ⊔ f c
Equations
- s.sup f = Finset.fold (fun (x1 x2 : α) => x1 ⊔ x2) ⊥ f s
Instances For
Alias of the reverse direction of Finset.sup_le_iff.
inf #
Infimum of a finite set: inf {a, b, c} f = f a ⊓ f b ⊓ f c
Equations
- s.inf f = Finset.fold (fun (x1 x2 : α) => x1 ⊓ x2) ⊤ f s
Instances For
Alias of the reverse direction of Finset.le_inf_iff.
Given nonempty finset s then s.sup' H f is the supremum of its image under f in (possibly
unbounded) join-semilattice α, where H is a proof of nonemptiness. If α has a bottom element
you may instead use Finset.sup which does not require s nonempty.
Instances For
Alias of the reverse direction of Finset.sup'_le_iff.
To rewrite from right to left, use Finset.sup'_comp_eq_image.
A version of Finset.sup'_image with LHS and RHS reversed.
Also, this lemma assumes that s is nonempty instead of assuming that its image is nonempty.
A version of Finset.sup'_map with LHS and RHS reversed.
Also, this lemma assumes that s is nonempty instead of assuming that its image is nonempty.
Given nonempty finset s then s.inf' H f is the infimum of its image under f in (possibly
unbounded) meet-semilattice α, where H is a proof of nonemptiness. If α has a top element you
may instead use Finset.inf which does not require s nonempty.
Instances For
To rewrite from right to left, use Finset.inf'_comp_eq_image.
A version of Finset.inf'_image with LHS and RHS reversed.
Also, this lemma assumes that s is nonempty instead of assuming that its image is nonempty.
A version of Finset.inf'_map with LHS and RHS reversed.
Also, this lemma assumes that s is nonempty instead of assuming that its image is nonempty.
Alias of Finset.sup_singleton_apply.
Alias of Finset.sup_singleton_eq_self.