Let Q be the set of all algebraic numbers. The naïve height h:Q→R is
defined as follows. Let α∈Q and let P(x) be an irreducible primitive polynomial with integers coefficients
such that P(α)=0. Let n be the degree and a be the leading coefficient of P(x). Then,
h(α):=n1log∣a∣+P(β)=0∑logmax(1,∣β∣).
The Zhang-Zagier height is the function
hZ:Q→R,hZ(α)=h(α)+h(1−α).
The essential minimum of the Zhang-Zagier height is the supremum C82 over all real numbers H such that the set {α∈Q∣hZ(α)≤H} is finite.