Evaluation of power series #
Power series in one indeterminate are the particular case of multivariate power series,
for the Unit
type of indeterminates.
This file provides a simpler syntax.
Let R
, S
be types, with CommRing R
, CommRing S
.
One assumes that IsTopologicalRing R
and UniformAddGroup R
,
and that S
is a complete and separated topological R
-algebra,
with IsLinearTopology S S
, which means there is a basis of neighborhoods of 0
consisting of ideals.
Given φ : R →+* S
, a : S
, and f : MvPowerSeries σ R
,
PowerSeries.eval₂ f φ a
is the evaluation of the power series f
at a
.
It f
is (the coercion of) a polynomial, it coincides with the evaluation of that polynomial.
Otherwise, it is defined by density from polynomials;
its values are irrelevant unless φ
is continuous and a
is topologically
nilpotent (a ^ n
tends to 0 when n
tends to infinity).
Under Continuous φ
and IsTopologicallyNilpotent a
,
the following lemmas furnish the properties of evaluation:
PowerSeries.eval₂Hom
: the evaluation of multivariate power series, as a ring morphism,PowerSeries.aeval
: the evaluation map as an algebra morphismPowerSeries.uniformContinuous_eval₂
: uniform continuity of the evaluationPowerSeries.continuous_eval₂
: continuity of the evaluationPowerSeries.eval₂_eq_tsum
: the evaluation is given by the sum of its monomials, evaluated.
We refer to the documentation of MvPowerSeries.eval₂
for more details.
Evaluation of a power series f
at a point a
.
It coincides with the evaluation of f
as a polynomial if f
is the coercion of a polynomial.
Otherwise, it is only relevant if φ
is continuous and a
is topologically nilpotent.
Equations
- PowerSeries.eval₂ φ a = MvPowerSeries.eval₂ φ fun (x : Unit) => a
Instances For
The evaluation homomorphism at a
on PowerSeries
, as a RingHom
.
Equations
- PowerSeries.eval₂Hom hφ ha = MvPowerSeries.eval₂Hom hφ ⋯
Instances For
For IsTopologicallyNilpotent a
,
the evaluation homomorphism at a
on PowerSeries
, as an AlgHom
.