An ordered blueprinted space, or OBlpr-space, is a topological space XX together with a sheaf OX\mathcal O_X of .

A morphism

(f,f#):(X,OX)⟶(Y,OY)(f,f^\#):(X,\mathcal O_X)\longrightarrow(Y,\mathcal O_Y)

consists of a continuous map f:X→Yf:X\to Y and a f#:OY→f∗OXf^\#:\mathcal O_Y\to f_*\mathcal O_X such that, for every x∈Xx\in X, the induced stalk map

fx#:OY,f(x)⟶OX,xf_x^\#:\mathcal O_{Y,f(x)}\longrightarrow\mathcal O_{X,x}

sends nonunits to nonunits. These objects and morphisms form the category OBlprSp\mathbf{OBlprSp}.

Unlike the definition of a , the definition does not require every stalk to have a unique . An is an OBlpr-space that is locally isomorphic to the spectrum of an ordered blueprint.

References

Matthew Baker and Oliver Lorscheid, The moduli space of matroids, §4.1.3.