Convex Bodies #
The file contains the definitions of several convex bodies lying in the space ℝ^r₁ × ℂ^r₂
associated to a number field of signature K
and proves several existence theorems by applying
Minkowski Convex Body Theorem to those.
Main definitions and results #
NumberField.mixedEmbedding.convexBodyLT
: The set of pointsx
such that‖x w‖ < f w
for all infinite placesw
withf : InfinitePlace K → ℝ≥0
.NumberField.mixedEmbedding.convexBodySum
: The set of pointsx
such that∑ w real, ‖x w‖ + 2 * ∑ w complex, ‖x w‖ ≤ B
NumberField.mixedEmbedding.exists_ne_zero_mem_ideal_lt
: LetI
be a fractional ideal ofK
. Assume thatf
is such thatminkowskiBound K I < volume (convexBodyLT K f)
, then there exists a nonzero algebraic numbera
inI
such thatw a < f w
for all infinite placesw
.NumberField.mixedEmbedding.exists_ne_zero_mem_ideal_of_norm_le
: LetI
be a fractional ideal ofK
. Assume thatB
is such thatminkowskiBound K I < volume (convexBodySum K B)
(seeconvexBodySum_volume
for the computation of this volume), then there exists a nonzero algebraic numbera
inI
such that|Norm a| < (B / d) ^ d
whered
is the degree ofK
.
Tags #
number field, infinite places
The convex body defined by f
: the set of points x : E
such that ‖x w‖ < f w
for all
infinite places w
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Equations
- ⋯ = ⋯
Equations
- ⋯ = ⋯
The fudge factor that appears in the formula for the volume of convexBodyLT
.
Equations
Instances For
The volume of (ConvexBodyLt K f)
where convexBodyLT K f
is the set of points x
such that ‖x w‖ < f w
for all infinite places w
.
This is a technical result: quite often, we want to impose conditions at all infinite places
but one and choose the value at the remaining place so that we can apply
exists_ne_zero_mem_ringOfIntegers_lt
.
A version of convexBodyLT
with an additional condition at a fixed complex place. This is
needed to ensure the element constructed is not real, see for example
exists_primitive_element_lt_of_isComplex
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The fudge factor that appears in the formula for the volume of convexBodyLT'
.
Equations
Instances For
The function that sends x : ({w // IsReal w} → ℝ) × ({w // IsComplex w} → ℂ)
to
∑ w, ‖x.1 w‖ + 2 * ∑ w, ‖x.2 w‖
. It defines a norm and it used to define convexBodySum
.
Equations
- NumberField.mixedEmbedding.convexBodySumFun x = ∑ w : NumberField.InfinitePlace K, ↑w.mult * (NumberField.mixedEmbedding.normAtPlace w) x
Instances For
The convex body equal to the set of points x : E
such that
∑ w real, ‖x w‖ + 2 * ∑ w complex, ‖x w‖ ≤ B
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The fudge factor that appears in the formula for the volume of convexBodyLt
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The bound that appears in Minkowski Convex Body theorem, see
MeasureTheory.exists_ne_zero_mem_lattice_of_measure_mul_two_pow_lt_measure
. See
NumberField.mixedEmbedding.volume_fundamentalDomain_idealLatticeBasis_eq
and
NumberField.mixedEmbedding.volume_fundamentalDomain_latticeBasis
for the computation of
volume (fundamentalDomain (idealLatticeBasis K))
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Let I
be a fractional ideal of K
. Assume that f : InfinitePlace K → ℝ≥0
is such that
minkowskiBound K I < volume (convexBodyLT K f)
where convexBodyLT K f
is the set of
points x
such that ‖x w‖ < f w
for all infinite places w
(see convexBodyLT_volume
for
the computation of this volume), then there exists a nonzero algebraic number a
in I
such
that w a < f w
for all infinite places w
.
A version of exists_ne_zero_mem_ideal_lt
where the absolute value of the real part of a
is
smaller than 1
at some fixed complex place. This is useful to ensure that a
is not real.
A version of exists_ne_zero_mem_ideal_lt
for the ring of integers of K
.
A version of exists_ne_zero_mem_ideal_lt'
for the ring of integers of K
.
Let I
be a fractional ideal of K
. Assume that B : ℝ
is such that
minkowskiBound K I < volume (convexBodySum K B)
where convexBodySum K B
is the set of points
x
such that ∑ w real, ‖x w‖ + 2 * ∑ w complex, ‖x w‖ ≤ B
(see convexBodySum_volume
for
the computation of this volume), then there exists a nonzero algebraic number a
in I
such
that |Norm a| < (B / d) ^ d
where d
is the degree of K
.