Documentation

LeanPool.MarkoffModP.RiemannRoch.RRspace.Basic

Riemann–Roch spaces L(D) #

This file defines the Riemann–Roch space of a divisor on a function field and its dimension ℓ(D).

@[instance_reducible]

The classical decidable equality on k(X) used by the coordinate places.

Equations
Instances For

    A function belongs to the Riemann–Roch space of D when its valuation at every place v is at most WithZero.exp (D v), i.e. ord_v f ≥ -D v in additive notation. The zero function belongs trivially since its valuation is 0.

    Equations
    • One or more equations did not get rendered due to their size.
    Instances For
      theorem MarkoffRiemannRoch.FunctionField.Chart.memRRspace.add_mem (k : Type u_1) (K : Type u_2) [Field k] [Field K] [Algebra (Polynomial k) K] [Algebra (RatFunc k) K] [IsScalarTower (Polynomial k) (RatFunc k) K] [FunctionField k K] [Algebra.IsSeparable (RatFunc k) K] {D : DivisorA k K} {f g : K} (hf : memRRspace k K D f) (hg : memRRspace k K D g) :
      memRRspace k K D (f + g)
      theorem MarkoffRiemannRoch.FunctionField.Chart.memRRspace.smul_mem (k : Type u_1) (K : Type u_2) [Field k] [Field K] [Algebra k K] [Algebra (Polynomial k) K] [Algebra (RatFunc k) K] [IsScalarTower k (Polynomial k) K] [IsScalarTower (Polynomial k) (RatFunc k) K] [FunctionField k K] [Algebra.IsSeparable (RatFunc k) K] {D : DivisorA k K} (c : k) {f : K} (hf : memRRspace k K D f) :
      memRRspace k K D (c • f)
      theorem MarkoffRiemannRoch.FunctionField.Chart.memRRspace.mul_mem (k : Type u_1) (K : Type u_2) [Field k] [Field K] [Algebra (Polynomial k) K] [Algebra (RatFunc k) K] [IsScalarTower (Polynomial k) (RatFunc k) K] [FunctionField k K] [Algebra.IsSeparable (RatFunc k) K] {D E : DivisorA k K} {f g : K} (hf : memRRspace k K D f) (hg : memRRspace k K E g) :
      memRRspace k K (D + E) (f * g)
      theorem MarkoffRiemannRoch.FunctionField.Chart.memRRspace.memRRspace_mono (k : Type u_1) (K : Type u_2) [Field k] [Field K] [Algebra (Polynomial k) K] [Algebra (RatFunc k) K] [IsScalarTower (Polynomial k) (RatFunc k) K] [FunctionField k K] [Algebra.IsSeparable (RatFunc k) K] {D E : DivisorA k K} (h : D ≤ E) {f : K} (hf : memRRspace k K D f) :
      memRRspace k K E f
      theorem MarkoffRiemannRoch.FunctionField.Chart.memRRspace.pow_mem (k : Type u_1) (K : Type u_2) [Field k] [Field K] [Algebra (Polynomial k) K] [Algebra (RatFunc k) K] [IsScalarTower (Polynomial k) (RatFunc k) K] [FunctionField k K] [Algebra.IsSeparable (RatFunc k) K] {D : DivisorA k K} {f : K} (hf : memRRspace k K D f) (n : ℕ) :
      memRRspace k K (n • D) (f ^ n)

      The Riemann–Roch space L(D).

      Equations
      Instances For

        Multiplication by a nonzero function identifies L(D + (x)) with L(D).

        Equations
        • One or more equations did not get rendered due to their size.
        Instances For

          Riemann–Roch dimensions are invariant under adding a principal divisor.

          The rank of the quotient L(D') / L(D) (with intersection semantics when unordered).

          Equations
          • One or more equations did not get rendered due to their size.
          Instances For

            One-step local residue map at a finite coordinate place.

            Equations
            • One or more equations did not get rendered due to their size.
            Instances For

              One-step local residue map at an infinite coordinate place.

              Equations
              • One or more equations did not get rendered due to their size.
              Instances For

                The local residue-field estimate for an increment of Riemann–Roch spaces.

                A function integral at every coordinate place is algebraic over the constant field.

                Rank-nullity for an inclusion of Riemann–Roch spaces.

                theorem MarkoffRiemannRoch.FunctionField.Chart.ell_le (k : Type u_1) (K : Type u_2) [Field k] [Field K] [Algebra k K] [Algebra (Polynomial k) K] [Algebra (RatFunc k) K] [IsScalarTower k (Polynomial k) K] [IsScalarTower (Polynomial k) (RatFunc k) K] [FunctionField k K] [Algebra.IsSeparable (RatFunc k) K] [IsFullConstantField k K] (D : DivisorA k K) :
                ↑(ell k K D) ≤ deg k K (D ⊔ 0) + 1
                theorem MarkoffRiemannRoch.FunctionField.Chart.ell_le_nonneg (k : Type u_1) (K : Type u_2) [Field k] [Field K] [Algebra k K] [Algebra (Polynomial k) K] [Algebra (RatFunc k) K] [IsScalarTower k (Polynomial k) K] [IsScalarTower (Polynomial k) (RatFunc k) K] [FunctionField k K] [Algebra.IsSeparable (RatFunc k) K] [IsFullConstantField k K] {D : DivisorA k K} (hD : 0 ≤ D) :
                ↑(ell k K D) ≤ deg k K D + 1
                theorem MarkoffRiemannRoch.FunctionField.Chart.defect_mono (k : Type u_1) (K : Type u_2) [Field k] [Field K] [Algebra k K] [Algebra (Polynomial k) K] [Algebra (RatFunc k) K] [IsScalarTower k (Polynomial k) K] [IsScalarTower (Polynomial k) (RatFunc k) K] [FunctionField k K] [Algebra.IsSeparable (RatFunc k) K] {D D' : DivisorA k K} (h : D ≤ D') :
                deg k K D - ↑(ell k K D) ≤ deg k K D' - ↑(ell k K D')