Convex bodies #
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This file contains the definition of the type convex_body V
consisting of
convex, compact, nonempty subsets of a real topological vector space V
.
convex_body V
is a module over the nonnegative reals (nnreal
) and a pseudo-metric space.
If V
is a normed space, convex_body V
is a metric space.
TODO #
- define positive convex bodies, requiring the interior to be nonempty
- introduce support sets
- Characterise the interaction of the distance with algebraic operations, eg
dist (a • K) (a • L) = ‖a‖ * dist K L
,dist (a +ᵥ K) (a +ᵥ L) = dist K L
Tags #
convex, convex body
- carrier : set V
- convex' : convex ℝ self.carrier
- is_compact' : is_compact self.carrier
- nonempty' : self.carrier.nonempty
Let V
be a real topological vector space. A subset of V
is a convex body if and only if
it is convex, compact, and nonempty.
Instances for convex_body
Equations
Equations
- convex_body.add_monoid = {add := λ (K L : convex_body V), {carrier := set.image2 has_add.add ↑K ↑L, convex' := _, is_compact' := _, nonempty' := _}, add_assoc := _, zero := {carrier := 0, convex' := _, is_compact' := _, nonempty' := _}, zero_add := _, add_zero := _, nsmul := nsmul_rec (add_zero_class.to_has_add (convex_body V)), nsmul_zero' := _, nsmul_succ' := _}
Equations
- convex_body.inhabited = {default := 0}
Equations
- convex_body.add_comm_monoid = {add := add_monoid.add convex_body.add_monoid, add_assoc := _, zero := add_monoid.zero convex_body.add_monoid, zero_add := _, add_zero := _, nsmul := add_monoid.nsmul convex_body.add_monoid, nsmul_zero' := _, nsmul_succ' := _, add_comm := _}
Equations
- convex_body.has_smul = {smul := λ (c : ℝ) (K : convex_body V), {carrier := c • ↑K, convex' := _, is_compact' := _, nonempty' := _}}
Equations
- convex_body.distrib_mul_action = {to_mul_action := {to_has_smul := convex_body.has_smul _inst_4, one_smul := _, mul_smul := _}, smul_zero := _, smul_add := _}
The convex bodies in a fixed space $V$ form a module over the nonnegative reals.
Equations
Convex bodies in a fixed seminormed space $V$ form a pseudo-metric space under the Hausdorff metric.
Equations
- convex_body.pseudo_metric_space = {to_has_dist := {dist := λ (K L : convex_body V), metric.Hausdorff_dist ↑K ↑L}, dist_self := _, dist_comm := _, dist_triangle := _, edist := λ (x y : convex_body V), ↑⟨(λ (K L : convex_body V), metric.Hausdorff_dist ↑K ↑L) x y, _⟩, edist_dist := _, to_uniform_space := uniform_space_of_dist (λ (K L : convex_body V), metric.Hausdorff_dist ↑K ↑L) convex_body.pseudo_metric_space._proof_6 convex_body.pseudo_metric_space._proof_7 convex_body.pseudo_metric_space._proof_8, uniformity_dist := _, to_bornology := bornology.of_dist (λ (K L : convex_body V), metric.Hausdorff_dist ↑K ↑L) convex_body.pseudo_metric_space._proof_10 convex_body.pseudo_metric_space._proof_11 convex_body.pseudo_metric_space._proof_12, cobounded_sets := _}
Convex bodies in a fixed normed space V
form a metric space under the Hausdorff metric.