Number Theory Note

Componentwise Height Bounds for Polynomial Value-Set Lifting

A componentwise height-counting theorem for the sparse exceptional set left after polynomial graph components are removed.

Summary

Result and mechanism

The note counts S-integer inputs a for which f(a) has a rational preimage under another polynomial g, after excluding the polynomial graph components coming from identities of the form f(x) = g(h(x)).

Main result

The main theorem separates the remaining contributions by component geometry. Active rational one-infinity components give the power-log terms; rational two-infinity components contribute only unit-theoretic polylogarithmic growth; the remaining components contribute finitely many inputs. A separate quadratic-source section isolates the square-root boundary and shows that it forces an affine involution of the source polynomial.

Contribution type
New argument; partial Lean formalization
Contribution
Componentwise sparse height bounds for polynomial value-set lifting after removing graph components.
Core mechanism
Graph removal, active one-infinity components, unit growth, quadratic source-even obstruction
arXiv
arXiv:2605.12903, submitted May 13, 2026; math.NT and math.AG
Lean scope
Section 7 algebra around affine involutions, source-even polynomials, odd-degree obstruction, and the parametrized quadratic-source converse.
Lean theorem family
HeightBoundsFormalization.QuadraticSources
Lean and mathlib
Lean 4.30.0-rc2, mathlib v4.30.0-rc2
Build command
lake build