A Uniform Divisor-Comparison Method for Meromorphic Identities

RESUMO

We present a uniform method for proving meromorphic function identities by comparing complete zero and pole multisets. A fixed annular Weierstrass normalization represents every nonzero meromorphic function uniquely as \[ q_t=e^{h_t}\frac{p_{Z_t}}{p_{P_t}},\qquad t=([h_t],Z_t,P_t),\qquad [h_t]\in\mathcal O(\mathbb C)/(2\pi i\mathbb Z). \] Thirteen principal comparisons, together with their specializations and consequences, use the same four steps: represent the two sides, compare their divisors, apply a divisor-comparison theorem (DCT), and normalize $h_s-h_t$. A small library packages classical finite-order, parity, recurrence, and lattice-rigidity arguments for repeated use. The examples span sine, Gamma, Barnes $G$, Bessel, completed zeta, theta, and elliptic functions. Their breadth demonstrates reuse of one proof structure across these families; the family-specific hypotheses and scalar calculations remain explicit. The contribution is a methodological synthesis: shorter proofs where available, and otherwise a modular organization of classical arguments. The fixed factors supply common coordinates, rather than a new uniqueness hypothesis. Historically, the viewpoint is motivated by the nineteenth-century contrast between Riemann's global geometric approach to complex function theory and Weierstrass's analytic construction of functions; the present method deliberately combines global divisor data with fixed Weierstrass factors. An appendix develops the associated ring and field presentations, separately from the ordinary operations used in the proofs.