A necessary and sufficient condition for Riemann's singularity theorem to hold on a Prym theta divisor

The Curve of “prym Canonical” Gauss Divisors on a Prym Theta Divisor

Introduction: A good understanding of the geometry of a theta divisor Θ of a principally polarized abelian variety (A,Θ) requires a knowledge of properties of its canonical linear system, the Gauss linear system |OΘ(Θ)|. A striking feature of the theta divisor Θ(C) of the Jacobian of a curve C is that the dual of the branch divisor of the associated Gauss map γΘ on Θ, is not a hypersurface as e...

A Necessary and Sufficient Condition for Transcendency

As has been known for many years (see, e.g., K. Mahler, /. Reine Angew. Math., v. 166, 1932, pp. 118-150), a real or complex number f is transcendental if and only if the following condition is satisfied. To every positive number co there exists a positive integer n and an infinite sequence of distinct polynomials {p,(z)} = {pr + pr z + • • • + p z } at most of 0 1 n degree n with integral coef...

A Riemann Singularities Theorem for Prym Theta Divisors, with Applications

Let (P,Ξ) be the naturally polarized model of the Prym variety associated to the étale double cover π : C̃ → C of smooth connected curves, where Ξ ⊂ P ⊂ Pic2g−2(C̃), and g(C) = g. If L is any “non exceptional” singularity of Ξ, i.e. a point L on Ξ ⊂ Pic2g−2(C̃) such that h0(C̃, L) ≥ 4, but which cannot be expressed as π∗(M)(B) for any line bundle M on C with h0(C,M) ≥ 2 and effective divisor B ≥ 0 ...

A Necessary and Sufficient Condition for Peace∗

This paper examines the possibility for two contestants to agree on a peace settlement thereby avoiding a contest, in which each would exert a costly effort given the posterior distributions inferred from the negotiation. I find a necessary and sufficient condition of the prior distributions for there to exist a negotiation mechanism that admits a peace-ensuring perfect Bayesian equilibrium. Th...

A Necessary Condition for Weyl-Heisenberg Frames