Published online by Cambridge University Press: 24 October 2008
The aim of this note is to prove
Theorem 1. Let n ≥ 3, and let p1, p2,…, Pn be primes in ℕ: = {z ∈ ℤ:z > 0}, each congruent to 1 (mod 4), which satisfy both of the following conditions:
(i) every unit in ℚ(√(p1p2)) has norm + 1;
(ii) the graph γ = γ(p1, p2, …, pn) associated with p1, p2, …, pn is odd (in the sense of [1]).