propositionroutine

Index congruence at every contact prime

At each contact prime qq, vq(a~−η(a))≥Kv_q(\widetilde a-\eta(a))\ge K for a∈Ra\in R
makes powers of contact radicals divide delta
Proposition·red:index-congruence·§2.6 Index congruences at every contact prime

Statement (paper)

Fix an ordinary K≥1K\ge1 and use the exceptional set SKS_K above. Choose a representation supplied at precision KK for an arbitrary A∈RA\in R, and put s~i=(u~i:v~)\widetilde s_i=(\widetilde u_i:\widetilde v). For every prime qq of ∗Z{}^*\Z counted by any MK(s~i)M_K(\widetilde s_i), and every a∈Ra\in R, the element a~\widetilde a is integral at qq and vq(a~−η(a))≥K. v_q(\widetilde a-\eta(a))\ge K.

In plain English

For ordinary K≥1K\ge1 and a representation at precision KK of any A∈RA\in R, at every prime qq of ∗Z{}^*\Z counted by some MK(s~i)M_K(\widetilde s_i), each a~\widetilde a with a∈Ra\in R is integral at qq and satisfies vq(a~−η(a))≥Kv_q(\widetilde a-\eta(a))\ge K.

Why it's here

This is the step that turns the local comparison lemma into a statement at every contact prime. The coarsening lemma supplies, from the odd valuation at qq, a tested branch and a place v∗v_* over qq at which localization membership gives the valuation bounds the comparison lemma needs. The resulting congruence of a~\widetilde a with the index η(a)\eta(a) modulo qKq^K is then used in the finite-test success argument, including the divisibility of δ\delta by MK(s~i)KM_K(\widetilde s_i)^K.
Classified routine:
Direct combination of the earlier coarsening lemma (choosing a tested branch and place over q) with the local comparison lemma to get the congruence at every contact prime; bookkeeping that assembles those two lemmas rather than a new idea.

Figures

A proof-flow diagram of six boxes connected by arrows. The left column starts with varying $A\in R$ and choosing a representation at precision $K$ with slopes $\widetilde s_i$, then passes to local analysis at each prime $q\mid M_K(\widetilde s_i)$ (pole parity and coarsening), then to the paired elliptic tests giving $v_q(\widetilde a-\eta(a))\ge K$. The right column keeps the root tuple fixed with nonzero $\delta=f(\eta(\mathbf a))$ bounded by $C_fB^D$; an arrow labeled 'polynomial evaluation' and an arrow from the tests feed a box concluding $M_K(\widetilde s_i)^K\mid\delta$. A final wide box applies the five-point height estimate to get $h(\widetilde A)\ll_f B$ uniformly for $A\in R$.
Figure 1diagramp. 16
The use of one nonzero δ\delta for every A∈RA\in R. All slopes shown come from the representation chosen at the fixed ordinary precision KK, and MKM_K uses the fixed exceptional set for KK. The comparison holds for every a∈Ra\in R, so it applies to the fixed root tuple. The implied constant in the final bound is ordinary and independent of AA and a\mathbf a.
What it shows
A proof-flow diagram of six boxes connected by arrows. The left column starts with varying A∈RA\in R and choosing a representation at precision KK with slopes s~i\widetilde s_i, then passes to local analysis at each prime q∣MK(s~i)q\mid M_K(\widetilde s_i) (pole parity and coarsening), then to the paired elliptic tests giving vq(a~−η(a))≥Kv_q(\widetilde a-\eta(a))\ge K. The right column keeps the root tuple fixed with nonzero δ=f(η(a))\delta=f(\eta(\mathbf a)) bounded by CfBDC_fB^D; an arrow labeled 'polynomial evaluation' and an arrow from the tests feed a box concluding MK(s~i)K∣δM_K(\widetilde s_i)^K\mid\delta. A final wide box applies the five-point height estimate to get h(A~)≪fBh(\widetilde A)\ll_f B uniformly for A∈RA\in R.
Read from the image by claude-opus-5.5 · confidence 85%

Sources

PaperOpen
Section
§2.6 Index congruences at every contact prime
Page
—
Label
red:index-congruence
Line
sections/02-reduction.tex:722
Leannot aligned

Phase 2 aligns this node to a Lean declaration.