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## Coarse Graining Presheaf on category of Boolean subalgebras

One can alternatively define a coarse graining presheaf directly on the category of Boolean subalgebras (see Category of Boolean subalgebras ).

**Definition 2.5**

*A*

**coarse graining presheaf**on is a contravariant functor 3.2 such that:- each object
gets mapped to itself i.e.

- given a -morphism such that the corresponding -morphism is

Cecilia Flori 2007-03-17