In this article, we give a complex-geometric proof of the Alexandrov-Fenchel
inequality without using toric compactifications. The idea is to use the
Legendre transform and develop the Brascamp-Lieb proof of the Pr\'ekopa
theorem. New ingredients in our proof include an integration of Timorin's mixed
Hodge-Riemann bilinear relation and a mixed norm version of H\"ormander's
L2-estimate, which also implies a non-compact version of the
Khovanski\u{i}-Teissier inequality.Comment: New version, "on line first" in Journal of Functional Analysis:
https://doi.org/10.1016/j.jfa.2018.01.01