Can I reason over GO?

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It is possible to do some reasoning over GO now, and we expect to do much more in the future. We provide logical definitions or 'cross-products' for some terms as part of the extended GO file, which can be reasoned over. The OWL version of GO is described in a conference paper Use of OWL within the Gene Ontology. To understand how the OWL version of GO relates to the OBO version, see the OBO Format documentation