The span of a set of vectors, as a submodule #
Submodule.span s
is defined to be the smallest submodule containing the sets
.
Notations #
- We introduce the notation
R ∙ v
for the span of a singleton,Submodule.span R {v}
. This is\.
, not the same as the scalar multiplication•
/\bub
.
The span of a set s ⊆ M
is the smallest submodule of M that contains s
.
Equations
- Submodule.span R s = sInf {p : Submodule R M | s ⊆ ↑p}
Instances For
An R
-submodule of M
is principal if it is generated by one element.
- principal' : ∃ (a : M), S = Submodule.span R {a}
Instances
A version of Submodule.span_eq
for when the span is by a smaller ring.
A version of Submodule.map_span_le
that does not require the RingHomSurjective
assumption.
Alias of Submodule.map_span
.
Alias of Submodule.map_span_le
.
Alias of Submodule.span_preimage_le
.
An induction principle for span membership. If p
holds for 0 and all elements of s
, and is
preserved under addition and scalar multiplication, then p
holds for all elements of the span of
s
.
An induction principle for span membership. This is a version of Submodule.span_induction
for binary predicates.
A dependent version of Submodule.span_induction
.
A variant of span_induction
that combines ∀ x ∈ s, p x
and ∀ r x, p x → p (r • x)
into a single condition ∀ r, ∀ x ∈ s, p (r • x)
, which can be easier to verify.
A dependent version of Submodule.closure_induction
.
span
forms a Galois insertion with the coercion from submodule to set.
Equations
- Submodule.gi R M = { choice := fun (s : Set M) (x : ↑(Submodule.span R s) ≤ s) => Submodule.span R s, gc := ⋯, le_l_u := ⋯, choice_eq := ⋯ }
Instances For
Equations
- Submodule.«term_∙_» = Lean.ParserDescr.trailingNode `Submodule.term_∙_ 1000 0 (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.symbol " ∙ ") (Lean.ParserDescr.cat `term 0))
Instances For
See Submodule.span_smul_eq
(in RingTheory.Ideal.Operations
) for
span R (r • s) = r • span R s
that holds for arbitrary r
in a CommSemiring
.
We can regard coe_iSup_of_chain
as the statement that (↑) : (Submodule R M) → Set M
is
Scott continuous for the ω-complete partial order induced by the complete lattice structures.
If R
is "smaller" ring than S
then the span by R
is smaller than the span by S
.
A version of Submodule.span_le_restrictScalars
with coercions.
Taking the span by a large ring of the span by the small ring is the same as taking the span by just the large ring.
f
is an explicit argument so we can apply
this theorem and obtain h
as a new goal.
An induction principle for elements of ⨆ i, p i
.
If C
holds for 0
and all elements of p i
for all i
, and is preserved under addition,
then it holds for all elements of the supremum of p
.
A dependent version of submodule.iSup_induction
.
The span of a finite subset is compact in the lattice of submodules.
The span of a finite subset is compact in the lattice of submodules.
Equations
- ⋯ = ⋯
A submodule is equal to the supremum of the spans of the submodule's nonzero elements.
For every element in the span of a set, there exists a finite subset of the set such that the element is contained in the span of the subset.
The product of two submodules is a submodule.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Equations
- ⋯ = ⋯
There is no vector subspace between p
and (K ∙ x) ⊔ p
, WCovBy
version.
There is no vector subspace between p
and (K ∙ x) ⊔ p
, CovBy
version.
Given an element x
of a module M
over R
, the natural map from
R
to scalar multiples of x
. See also LinearMap.ringLmapEquivSelf
.
Equations
- LinearMap.toSpanSingleton R M x = LinearMap.smulRight LinearMap.id x
Instances For
The range of toSpanSingleton x
is the span of x
.
Two linear maps are equal on Submodule.span s
iff they are equal on s
.
If two linear maps are equal on a set s
, then they are equal on Submodule.span s
.
This version uses Set.EqOn
, and the hidden argument will expand to h : x ∈ (span R s : Set M)
.
See LinearMap.eqOn_span
for a version that takes h : x ∈ span R s
as an argument.
If two linear maps are equal on a set s
, then they are equal on Submodule.span s
.
See also LinearMap.eqOn_span'
for a version using Set.EqOn
.
If s
generates the whole module and linear maps f
, g
are equal on s
, then they are
equal.
If the range of v : ι → M
generates the whole module and linear maps f
, g
are equal at
each v i
, then they are equal.
Given a nonzero element x
of a torsion-free module M
over a ring R
, the natural
isomorphism from R
to the span of x
given by $r \mapsto r \cdot x$.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Given a nonzero element x
of a torsion-free module M
over a ring R
, the natural
isomorphism from the span of x
to R
given by $r \cdot x \mapsto r$.
Equations
- LinearEquiv.coord R M x h = LinearEquiv.symm (LinearEquiv.toSpanNonzeroSingleton R M x h)