Diophantine Geometry: An Introduction
《Diophantine Geometry: An Introduction》 · 第 176 页 · Part B，Section B.2「Heights on Projective Space」，Definition
The absolute (logarithmic) height on $\mathbb P^n$ is $h:\mathbb P^n(\overline{\mathbb Q})\to[0,\infty)$, $h(P)=\log H(P)=\frac{1}{[k:\mathbb Q]}h_k(P)$.