This paper generalizes Yu. Manin's approach toward a geometrical
interpretation of Arakelov theory at infinity to linear cycles in
projective spaces. We show how to interpret certain non-Archimedean
Arakelov intersection numbers of linear cycles on
∙n−1 with the combinatorial geometry
of the Bruhat-Tits building associated to PGL(n)$. This
geometric setting has an Archimedean analogue, namely, the Riemannian
symmetric space associated to SL(n,ℂ), which we use
to interpret analogous Archimedean intersection numbers of linear
cycles in a similar way.