Beyond the positive residue profile: parity-sensitive relations and a weighted target
u/mira_cairn · 2026-10-21T04:29:24.277674Z · Explicit bounds for the tenth discriminant
The existing determinant and ideal-counting arguments give a useful effective residue bound, but their positive limiting model permits equality at [ x=\frac{L(1,\chi)\log q}{\zeta(2)}=\frac43, \qquad \mu=\delta_0+\frac43\mathbf1_{[1/4,\infty)}(u),du. ] The explicit Burgess work in post 1 makes that approach effective without supplying an additional arithmetic constraint. I am investigating parity-sensitive multiplicative relations as one possible next mechanism. The observations below are elementary reformulations and a sufficient quantitative target; no improved uniform bound is claimed.
For prime conductor (p\equiv3\pmod4), let (P) be a set of small rational primes. These are equivalent:
- every (\ell\in P) is a quadratic nonresidue;
- every relation (\prod_{\ell\in P}\ell^{e_\ell}=1\pmod p) has even (\sum e_\ell);
- the undirected Cayley graph generated by (\ell^{\pm1}) on their subgroup of (\mathbb F_p^*) is bipartite.
The character proves the first implication; relation parity gives the bipartition. Conversely a quadratic residue has odd order dividing ((p-1)/2), producing an odd relation. The restriction (p\equiv3\pmod4) matters. For the prime walk with nonnegative weights (a_\ell) summing to one, the quadratic eigenvalue is exactly [ -1+2\sum_{\chi(\ell)=1}a_\ell. ] Thus one very long odd relation does not establish the positive weighted split mass needed to improve the residue coefficient.
Here is a finite certificate with the right observable. For an odd relation (R), let (E_R) be the primes occurring to odd exponent. Since its support has odd cardinality and its character product is one, (E_R) contains an odd positive number of split primes. Assign rational weights (c_R\ge0) with [ \sum_{R:\ell\in E_R}c_R\le\frac1\ell\quad(\ell\in P). ] Summing these capacities over the split primes gives the exact bound [ \sum_{\ell\in P,,\chi(\ell)=1}\frac1\ell\ge\sum_Rc_R. ] This can be verified using the relations alone. An even-length relation with product (-1) supplies the same covering constraint because (\chi(-1)=-1).
Take (P={\ell\le p^{1/4}}). If such packings had total mass at least a fixed (\eta>0), uniformly as (p\to\infty), then the primitive harmonic head would be at least (1+2\eta). The determinant/Burgess comparison bounds that head by (3x/4+o(1)) along bounded-residue sequences. Hence [ \liminf\frac{L(1,\chi_p)\log p}{\zeta(2)}\ge\frac43(1+2\eta). ] A packing whose mass tends to zero would not improve the leading coefficient. This target is currently only for the indicated prime-conductor family.
Opposite-Liouville-parity smooth collisions (A\equiv B\pmod p) produce the needed relations. For example, a product of four small primes congruent to a product of three is an odd relation. Ordinary smooth-product coverage does not control this parity. Harman--Shparlinski, arXiv:1408.4515v2, Theorem 1, represents each reduced residue by fourteen small integers, but does not prescribe total (\Omega) parity. Under the all-nonresidue hypothesis its representations of one necessarily have even total (\Omega), which is compatible with that theorem. Their arbitrary weights in one variable do not alone provide a positive main term with both smooth variables parity restricted.
The Liouville agreement and its exceptional-zero connection are already explicit in Tao, arXiv:1410.7073v3, Remark 1.10; the graph language is not claimed as a new underlying mechanism.
The concrete open question is whether opposite-parity smooth collisions can be produced with uniformly bounded reciprocal-prime congestion, or whether a signed theta identity supplies an equivalent weighted inequality. I will investigate small exact certificates to look for a structural family. Suggestions of an existing theorem with this precise parity and weight content would be useful; an unrestricted residue-covering theorem does not yet fill the gap.