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Totally real towers

Totally real towers

Totally real number-field towers and their unramified pro-p Galois groups. Includes Frobenius constraints, finite-support comparisons and relation-rank bounds.

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Multiplication by the actual character of negative three switches the real value and leaves inertia at every finite place other than three unchanged. This constructs a character with any specified real value, starting wi…

The real local Artin value of negative one is complex conjugation whenever an infinite place ramifies. If a discrete absolute representation kills these actual elements over a totally real base, its finite Galois kernel…

A discrete p-group representation killing finite inertia outside the chosen support and the real Artin value of negative one has an actual finite Galois kernel field satisfying the defining local conditions. Its inclusio…

The actual ambient inclusion supplies a continuous surjective restriction homomorphism. Its kernel is exactly the subgroup fixing the constructed compositum. The quotient by this kernel is continuously isomorphic to the…

Absolute inertia outside the allowed support fixes every admissible finite layer, hence their compositum. Real Artin conjugation fixes that compositum because every complex embedding of it is real.

All.lean0 declarations

Totally real number-field towers and their unramified pro-p Galois groups. Includes Frobenius constraints, finite-support comparisons and relation-rank bounds.

A vanishing finite field-unit class gives an actual field-unit primitive. The existing Hilbert-90 correction then gives a continuous lift of the normalized central extension over the absolute Galois group. Thus its infla…

The finite coefficient map is composed with the established discrete continuous-to-ordinary H² comparison. Normalization changes a representative by the boundary of a constant one-cochain. The representative-level Hilber…

Restrict the chosen absolute valuation to the actual finite Galois layer. An absolute decomposition automorphism preserves this restricted valuation class. Complete splitting makes its decomposition group trivial, indepe…

The existing local residue comparison identifies the quotient by inertia with the profinite integers. The class of arithmetic Frobenius is the inverse image of additive one, and a representative is chosen in the actual a…

We select actual finite Galois intermediate fields of the fixed algebraic closure of ℚ. The base field is a member and binary composita remain in the family. These constructors provide the directed family used to form th…

Compact intermediate fields contained in the supremum of admissible finite layers lie in one layer, since the family is nonempty and directed. This applies both to finite-dimensional intermediate fields and to the field…

The concrete finite Galois compositum equals the field generated by its five square roots. Independence of their rational square classes gives its degree by the general finite-adjoin induction.

The radicands 5, 13, 17, 21, 33 have no nonempty square subproduct. There are exactly thirty-one nonempty subsets. The natural-number check uses the square-root decision procedure inside the Lean kernel; the rational sta…

The fixed field of an intersection of closed subgroups is the compositum of their fixed fields. The comparison uses the infinite Galois correspondence.

Depths n + 5 leave a strict negative Golod--Shafarevich margin at t = 5/12. This numerical file does not assert that the required Frobenius elements or their deep lifts have already been constructed.

Restriction embeds the automorphism group of a compositum of normal subextensions into the product of their automorphism groups. Consequently, p-group automorphism groups are preserved by composita. This applies in parti…

Complex conjugation in the algebraic closure restricts to the chosen negative-one Artin value in every finite abelian subextension. These finite projections identify its maximal-abelian restriction with the actual idele…

Forgetting the splitting conditions in Sawin's theorem gives totally real number fields of unbounded degree with uniformly bounded root discriminant.

Every finite normal subextension of the constructed compositum is contained in an admissible finite layer. Restriction therefore makes its Galois group a quotient of a p-group. Applying this to fixed fields of open norma…

The field is formed from the concrete directed family of finite layers. Galoisness and total reality follow from the corresponding properties of those layers. The pro-p property and arithmetic rank estimates are separate…

A finite family of independent square classes gives an actual extension of degree two to the power of the family size. Degree and square-class classification are proved simultaneously: classification in the previous laye…

Restriction to the actual field generated by a square root of negative three gives a continuous character of the absolute Galois group of the rationals. Its discriminant proves that it kills finite inertia away from thre…

Global reciprocity applied to the principal idele of negative one identifies its local value at three with its nontrivial real sign. All other finite components disappear by the proved unramifiedness of the actual quadra…

ProTwoFrattini.lean3 declarations

The finite-quotient definition of the profinite Frattini subgroup is equivalent to intersection over open normal subgroups of index two. For the reverse inclusion, each maximal subgroup of a finite two-group quotient pul…

A positive squarefree integer congruent to one modulo four determines an actual quadratic field in the fixed algebraic closure. Its Galois group has order two, its embeddings are real, and its discriminant is the given i…

QuadraticBasis.lean5 declarations

A generator of a quadratic extension of ℚ supplies the actual basis 1, α. Reindexing its power basis by Fin 2 gives named basis vectors and the rational coordinates of every element. No square relation is needed for this…

The actual rational basis 1, α, where α² = d, has diagonal trace matrix with entries 2 and 2d. Its discriminant is therefore 4d. No integrality or squarefreeness assumption is needed.

QuadraticClosure.lean12 declarations

A chosen square root of a nonsquare rational number generates an actual finite Galois intermediate field of degree two. Its internal generator, square relation, and generation theorem let later arithmetic constructions s…

A root of the same quadratic equation generates the same subfield of the fixed algebraic closure. This identifies arbitrary quadratic layers with the concrete constructors and makes squarefree radicands unique.

An intermediate field containing square roots of finitely many radicands also contains a square root of their product, up to a square in the base field. The proof constructs that root as an actual product and compares th…

The constructed bases of the full ring of integers determine the number field discriminant. Integer traces agree with rational traces after scalar extension, so the two-by-two trace determinants give 4d or d according to…

The nontrivial square root of unity in ℚ makes every quadratic extension a Kummer extension. The resulting generator has irreducible polynomial X ^ 2 - C d, which forces its rational square d to be nonzero and nonsquare.…

The square-root generator is integral. When its square is one modulo four, its half-integer translate is integral as well. Integer-coordinate classification gives spanning, and the concrete rational quadratic basis gives…

The trace and norm conditions and their parity criterion give integer coordinates for every algebraic integer. Away from d = 1 modulo four the generators are 1, α. Every algebraic integer also has integer coordinates in…

The trace and norm of an algebraic integer are integral. For a square-root generator of signed squarefree square d, these identities force both coordinates to be half-integers and give the congruence modulo four. Convers…

A square root of an integer is integral. More generally, the element (m + n α) / 2, where α ^ 2 = d, is integral whenever 4 ∣ m ^ 2 - d n ^ 2. The divisibility witness supplies the integer constant coefficient of the mon…

For a signed squarefree integer d, the norm numerator a² - d b² is divisible by four precisely for even coordinates, or for odd coordinates when d is one modulo four.

QuadraticReality.lean2 declarations

A square root of a nonnegative rational number has real image under every complex embedding. If it generates the extension, conjugation fixes the whole image. Conversely, a rational number that is a square in a totally r…

Two signed squarefree integers in the same rational square class agree. Taking traces in a quadratic field shows that any two square-root generators have squares in the same rational square class. Thus the normalized rad…

In a quadratic extension generated by a square root of a, an element of the base field becomes a square precisely when its square class is trivial or that of a. The basis 1, α makes the cross coefficient of a square expl…

Rescaling a rational Kummer generator by a nonzero rational number preserves the generated field and replaces its square by a signed squarefree integer.

A totally real quadratic number field has a positive squarefree integer radicand. If its allowed finite ramification support excludes two, the discriminant formula forces the radicand to be one modulo four. The discrimin…

QuadraticTrace.lean6 declarations

A square-root generator of a quadratic extension has minimal polynomial X² - d. Its trace and norm, and those of every rational linear combination of 1 and the generator, follow from the power basis and a two-dimensional…

The initial arithmetic group in the Sawin construction permits ramification at specified finite places. This predicate retains the existing local unramifiedness condition outside that set. Its tower lemmas work also for…

Inertia at a prime outside the permitted support is trivial on each factor. The restrictions to the factors jointly detect automorphisms of their compositum. This argument does not require an odd extension degree.

Class number one makes the actual unit-to-radical map surjective. The integral units of the rationals are ±1, so these two representatives exhaust the ideal-square radical. This identifies its unique possible obstruction…

The canonical identification of the integers of ℚ with ℤ identifies their local unramifiedness conditions. Under the equivalence between finite places of ℚ and positive rational primes, the allowed ramification support t…

Apply the natural-number squarefree decomposition to the product of the absolute numerator and denominator. The numerator's sign then gives an integer representative without introducing a square root in an extension.

Local unramified degree-two vanishing constructs the reference lifts. The actual absolute lift has finite ramification support; its differences from these reference lifts are genuine local characters. Prime three absorbs…

The finite-support radical kernel constructs an absolute quadratic character with the prescribed inertia values. Multiplication by the character of negative three then gives any specified real value while preserving iner…

The rational ideal-square radical is generated by the actual class of −1. The local restriction of the character of ℚ(√−3) has nonzero reciprocity pairing with that class. Subtracting its uniquely determined scalar multi…

RealCompositum.lean2 declarations

The initial Sawin tower has base field ℚ. Over this base, being unramified at infinite places is exactly total reality. Total reality is preserved by composita inside an algebraic extension, so this supplies the real-pla…

An actual quotient of a finitely generated profinite group admits finite arithmetic stages such that every element trivial on that stage has a lift of any prescribed augmentation depth in the source.

Outside the allowed support inertia acts trivially. Consequently the actual decomposition map factors through its residue-degree quotient; killing arithmetic Frobenius kills its entire decomposition image.

The closed normal subgroup generated by the chosen arithmetic Frobenii has a Hausdorff group quotient. At primes outside the allowed ramification support, its projection kills the whole absolute decomposition group.

Take the fixed field of the constructed closed normal subgroup inside the maximal real extension, then lift it into the same algebraic closure of ℚ. Its Galois group is the actual quotient from S3.

The actual quotient kills the absolute decomposition groups at selected unramified primes. Thus those groups fix the cut field elementwise. The proved restriction-image theorem for decomposition groups then gives complet…

The actual arithmetic Frobenius is represented by an absolute decomposition element. Complete splitting makes its finite-stage restriction trivial, so the constructed depth-detecting stage supplies a deep source lift.

An open normal subgroup determines an actual finite Galois fixed field. Lifting it to the chosen algebraic closure gives an admissible finite layer. The quotient is identified with that layer's Galois group. No rank esti…

The global ramification certificates on an admissible finite layer imply the actual chosen-completion conditions used by finite H² localization.

The actual finite quotient is continuously identified with the Galois group of its lifted fixed field. Its restriction map agrees with restriction from the fixed algebraic closure, by the actions of both maps on every fi…

The actual finite stage detecting source depth has completely split rational primes congruent to one modulo four outside any finite set. Excluding also the six allowed ramified primes gives an actual new unramified Frobe…

The group-theoretic intersection over quadratic quotients and the arithmetic classification of all quadratic layers identify the actual Frattini fixed field. No finite-generation hypothesis is used.

The proved Frattini fixed-field comparison identifies the canonical power--commutator quotient with the Galois group of the five quadratic layers. Its cardinality is therefore thirty-two. No finite-generation, quotient-f…

The finite-rank free source is an actual completion of an abstract free group. Its epimorphism to the arithmetic group has kernel in the Frattini subgroup.

Choose genuine primes and source lifts at depths n + 5 in the actual minimal presentation from S1. The prescribed finite-prefix budget allows all these Frobenius relations to be imposed while the quotient stays infinite.

The computed power--commutator quotient has order 32. Its vector-space basis lifts to a finite generating set of the actual Galois group by the pro-p Burnside criterion. The quotient dimension also proves minimality.

An actual absolute cocycle lift is corrected at its finite ramification support and at real conjugation. Its kernel field is an admissible finite real two-extension, so the corrected lift factors through the constructed…

At every actual finite arithmetic stage the field-unit Kummer image has at most 64 elements. Its kernel is killed by inflation to the constructed maximal group. Discrete comparison and the finite-stage Galois equivalence…

The arithmetic H² bound and the constructed five-generator quotient supply a finite minimal presentation. Its relation rank is at most six, so the Golod--Shafarevich criterion proves that the actual Galois group is infin…

Choose a presentation attaining the least relation count constructed in S1. Minimality identifies its displayed generator count with the actual rank five. The same presentation, including its free source and relators, is…

Finite Galois layers inside the maximal real extension correspond to open normal subgroups. Restricting and then lifting recovers the original ambient field. The index-degree equality identifies its quadratic layers, who…

The degree of every finite admissible layer is a power of two. Its ramified rational primes belong to {3,5,7,11,13,17}, whose product is 255255. The prime-to-degree different bound gives the same root scale 255255 for ev…

A single infinite set of rational primes congruent to one modulo four splits completely in totally real number fields of unbounded degree and uniformly bounded root discriminant. The statement matches the arithmetic inpu…

The finite set of allowed places is the actual six-prime support, with cardinality six. It provides the coordinate set used by H² localization.

The ramification and discriminant classification supplies a positive squarefree radicand for every quadratic layer. Its explicit square-class factorization then places that layer inside the compositum of the five chosen…

The radicands 5, 13, 17, 21, 33 give actual finite Galois fields inside the chosen algebraic closure of ℚ. Each satisfies the prescribed finite ramification and real-place conditions. Their finite supremum is therefore a…

Restriction to the two factors of a compositum is jointly injective. An exponent bound on both Galois groups therefore holds on their compositum. Each of the five chosen quadratic fields has Galois group of order two, so…

A squarefree integer supported on 3, 5, 7, 11, 13, 17 divides their product. The primes 5, 13, 17 are one modulo four, while an even subset of 3, 7, 11 contributes 1, 21, 33, or 77. The last contribution is 21 33 / 3². T…

SixPrimeSupport.lean4 declarations

The finite place support is the inverse image of the six primes under the canonical equivalence between finite places of ℚ and rational primes.

SquareRootAdjoin.lean5 declarations

Over any base field, a square root of a nonsquare has minimal polynomial X² - a and generates an extension of degree two. No assumption on the characteristic or on the ambient extension is required.

If a signed squarefree integer times the square of a rational number is integral, the denominator squared divides the squarefree integer. Coprimality of the rational numerator and denominator then forces the denominator…

This aggregate collects global reciprocity characters, idele cohomology, class groups, unramified composita, and maximal everywhere-unramified pro-p extensions.

This file identifies the power--commutator quotient of the maximal everywhere- unramified pro-p Galois group with the elementary Hilbert class-field layer. For odd p, it then identifies the topological generator rank wit…

The rational idele-class formation satisfies the cyclic class-field axiom. The abstract p-group induction therefore gives degree-one vanishing. Here we transport that source theorem to the actual relative idele-class rep…

The dense copy of the infinite cyclic group in ZHat has the expected universal property. A map to a finite discrete group factors through the cyclic quotient determined by the order of the image of 1; the finite-quotient…

The rank-one free-profinite property of ZHat splits the compact profinite central extension attached to every continuous homogeneous two-cocycle. The section supplies an explicit degree-one primitive, so continuous degre…

This aggregate collects absolute and finite Kummer comparisons, local Artin and Hilbert pairings, localization at finite places, and cyclic degree-two norm quotients.

The standard algebraic-closure Kummer character is transported to the local separable-closure model. Its kernel is the stabilizer of the chosen simple Kummer root, without imposing a residue-characteristic restriction.

This aggregate collects unramified fixed fields and common extensions, local units cohomology, cyclic restriction maps, and finite-place localization comparisons.

This file defines the field elements whose principal fractional ideals are positive powers, quotients them by field powers, and maps the resulting radical onto the matching torsion subgroup of the ordinary ideal class gr…

This file computes the cardinality and ZMod p-dimension of the ordinary number-field unit group modulo p-th powers. The torsion correction is one exactly when the field contains a primitive p-th root of unity. The module…