Adic valuations on Dedekind domains #
Given a Dedekind domain R
of Krull dimension 1 and a maximal ideal v
of R
, we define the
v
-adic valuation on R
and its extension to the field of fractions K
of R
.
We prove several properties of this valuation, including the existence of uniformizers.
We define the completion of K
with respect to the v
-adic valuation, denoted
v.adicCompletion
, and its ring of integers, denoted v.adicCompletionIntegers
.
Main definitions #
IsDedekindDomain.HeightOneSpectrum.intValuation v
is thev
-adic valuation onR
.IsDedekindDomain.HeightOneSpectrum.valuation v
is thev
-adic valuation onK
.IsDedekindDomain.HeightOneSpectrum.adicCompletion v
is the completion ofK
with respect to itsv
-adic valuation.IsDedekindDomain.HeightOneSpectrum.adicCompletionIntegers v
is the ring of integers ofv.adicCompletion
.
Main results #
IsDedekindDomain.HeightOneSpectrum.intValuation_le_one
: Thev
-adic valuation onR
is bounded above by 1.IsDedekindDomain.HeightOneSpectrum.intValuation_lt_one_iff_dvd
: Thev
-adic valuation ofr ∈ R
is less than 1 if and only ifv
divides the ideal(r)
.IsDedekindDomain.HeightOneSpectrum.intValuation_le_pow_iff_dvd
: Thev
-adic valuation ofr ∈ R
is less than or equal toMultiplicative.ofAdd (-n)
if and only ifvⁿ
divides the ideal(r)
.IsDedekindDomain.HeightOneSpectrum.intValuation_exists_uniformizer
: There existsπ ∈ R
withv
-adic valuationMultiplicative.ofAdd (-1)
.IsDedekindDomain.HeightOneSpectrum.valuation_of_mk'
: Thev
-adic valuation ofr/s ∈ K
is the valuation ofr
divided by the valuation ofs
.IsDedekindDomain.HeightOneSpectrum.valuation_of_algebraMap
: Thev
-adic valuation onK
extends thev
-adic valuation onR
.IsDedekindDomain.HeightOneSpectrum.valuation_exists_uniformizer
: There existsπ ∈ K
withv
-adic valuationMultiplicative.ofAdd (-1)
.
Implementation notes #
We are only interested in Dedekind domains with Krull dimension 1.
References #
- [G. J. Janusz, Algebraic Number Fields][janusz1996]
- [J.W.S. Cassels, A. Frölich, Algebraic Number Theory][cassels1967algebraic]
- [J. Neukirch, Algebraic Number Theory][Neukirch1992]
Tags #
dedekind domain, dedekind ring, adic valuation
Adic valuations on the Dedekind domain R #
The additive v
-adic valuation of r ∈ R
is the exponent of v
in the factorization of the
ideal (r)
, if r
is nonzero, or infinity, if r = 0
. intValuationDef
is the corresponding
multiplicative valuation.
Equations
- v.intValuationDef r = if r = 0 then 0 else ↑(Multiplicative.ofAdd (-↑((Associates.mk v.asIdeal).count (Associates.mk (Ideal.span {r})).factors)))
Instances For
Nonzero elements have nonzero adic valuation.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation_ne_zero
.
Nonzero elements have nonzero adic valuation.
Nonzero divisors have nonzero valuation.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation_ne_zero'
.
Nonzero divisors have nonzero valuation.
Nonzero divisors have valuation greater than zero.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation_zero_le
.
Nonzero divisors have valuation greater than zero.
The v
-adic valuation on R
is bounded above by 1.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation_le_one
.
The v
-adic valuation on R
is bounded above by 1.
The v
-adic valuation of r ∈ R
is less than 1 if and only if v
divides the ideal (r)
.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation_lt_one_iff_dvd
.
The v
-adic valuation of r ∈ R
is less than 1 if and only if v
divides the ideal (r)
.
The v
-adic valuation of r ∈ R
is less than Multiplicative.ofAdd (-n)
if and only if
vⁿ
divides the ideal (r)
.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation_le_pow_iff_dvd
.
The v
-adic valuation of r ∈ R
is less than Multiplicative.ofAdd (-n)
if and only if
vⁿ
divides the ideal (r)
.
The v
-adic valuation of 0 : R
equals 0.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation.map_zero'
.
The v
-adic valuation of 0 : R
equals 0.
The v
-adic valuation of 1 : R
equals 1.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation.map_one'
.
The v
-adic valuation of 1 : R
equals 1.
The v
-adic valuation of a product equals the product of the valuations.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation.map_mul'
.
The v
-adic valuation of a product equals the product of the valuations.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation.le_max_iff_min_le
.
The v
-adic valuation of a sum is bounded above by the maximum of the valuations.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation.map_add_le_max'
.
The v
-adic valuation of a sum is bounded above by the maximum of the valuations.
The v
-adic valuation on R
.
Equations
- v.intValuation = { toFun := v.intValuationDef, map_zero' := ⋯, map_one' := ⋯, map_mul' := ⋯, map_add_le_max' := ⋯ }
Instances For
There exists π ∈ R
with v
-adic valuation Multiplicative.ofAdd (-1)
.
Alias of IsDedekindDomain.HeightOneSpectrum.intValuation_exists_uniformizer
.
There exists π ∈ R
with v
-adic valuation Multiplicative.ofAdd (-1)
.
The I
-adic valuation of a generator of I
equals (-1 : ℤₘ₀)
Adic valuations on the field of fractions K
#
The v
-adic valuation of x ∈ K
is the valuation of r
divided by the valuation of s
,
where r
and s
are chosen so that x = r/s
.
Equations
- v.valuation = v.intValuation.extendToLocalization ⋯ K
Instances For
The v
-adic valuation of r/s ∈ K
is the valuation of r
divided by the valuation of s
.
The v
-adic valuation on K
extends the v
-adic valuation on R
.
The v
-adic valuation on R
is bounded above by 1.
The v
-adic valuation of r ∈ R
is less than 1 if and only if v
divides the ideal (r)
.
There exists π ∈ K
with v
-adic valuation Multiplicative.ofAdd (-1)
.
Uniformizers are nonzero.
Completions with respect to adic valuations #
Given a Dedekind domain R
with field of fractions K
and a maximal ideal v
of R
, we define
the completion of K
with respect to its v
-adic valuation, denoted v.adicCompletion
, and its
ring of integers, denoted v.adicCompletionIntegers
.
K
as a valued field with the v
-adic valuation.
Equations
- v.adicValued = Valued.mk' v.valuation
Instances For
The completion of K
with respect to its v
-adic valuation.
Instances For
Equations
- IsDedekindDomain.HeightOneSpectrum.instFieldAdicCompletion K v = UniformSpace.Completion.instField
Equations
- IsDedekindDomain.HeightOneSpectrum.instInhabitedAdicCompletion K v = { default := 0 }
Equations
- IsDedekindDomain.HeightOneSpectrum.valuedAdicCompletion K v = Valued.valuedCompletion
Equations
- ⋯ = ⋯
Equations
- IsDedekindDomain.HeightOneSpectrum.adicCompletion.instCoe K v = inferInstance
The ring of integers of adicCompletion
.
Equations
- IsDedekindDomain.HeightOneSpectrum.adicCompletionIntegers K v = Valued.v.valuationSubring
Instances For
Equations
Equations
- ⋯ = ⋯
Equations
- ⋯ = ⋯
Equations
- ⋯ = ⋯
Equations
- One or more equations did not get rendered due to their size.
The valuation on the completion agrees with the global valuation on elements of the integer ring.
The valuation on the completion agrees with the global valuation on elements of the field.
A global integer is in the local integers.
Equations
- ⋯ = ⋯
Equations
- ⋯ = ⋯