The projective spectrum as a distributive lattice

The projective spectrum as a distributive lattice. pdf
with Thierry Coquand and Peter Schuster
Cahiers de Topologie et Géométrie différentielles catégoriques. 48, (2007), 220-228.

Abstract : We construct a distributive lattice whose prime filters correspond to the homogeneous prime ideals of a graded commutative ring. This is the prime example of a non--affine scheme in a point--free context, and a specific case of a fairly general glueing method for distributive lattices.