Functoriality probes over number fields by mixed zero correlations

Abstract

We use an automorphic L-function over one number field as a probe for the functorial structure of another automorphic L-function over a possibly different field. No automorphic induction is assumed. We first determine the mixed Euler factors arising from the explicit formula, including the residue-degree multiplicities that occur when local traces are grouped by absolute norm. This local analysis gives four probe constructions. Rational-field probes with known base change detect constituent multiplicities and, in equal rank, exact Satake equalities. Probes over a common Galois field detect conjugacy and stabilizers. Dirichlet-character probes give congruence-weighted combinations of Satake traces even when the leading overlap vanishes. A tensor-product construction realizes general different-field probes whenever the required base changes exist. We then separate the pair calculation from the higher connected calculations and work out the cubic and quartic arithmetic explicitly. In an explicit small Fourier box these expressions yield all finite secondary orders of the centered statistics; the required pair prime number theorems also give raw and distinct-index correlations. The main analytic tools are an independent fixed-data proof of Hypothesis H over number fields, a positive-margin estimate for rationally grouped coefficients, and the theorem of Harcos-Thorner for the realized Rankin-Selberg factors. This expanded version includes the full computations, local examples, and an appendix explaining the character-extension issue avoided by the proof of Hypothesis H. The resulting probes give concrete tests of functorial relationships, while recovery of automorphic induction remains a longer-term goal.