logical operators in Modelseed GPR

Question

[mary]

Hi there I have been working with Modelseed driven network reconstructs and have problems understanding the logical operator and parenthesis' meanings in some reaction's GPR (file in xls format);

(geneA and geneA) the product of geneA is a homodimer? (geneA or geneA) the produced protein has two active sites? ((geneA or geneB) or geneC) the genes in the internal parentheses are Modelseed's predicted genes coding a protein involved in the reaction and the other one (geneC) is a gene that the involvement of its product in the reaction has been mentioned elsewhere, e g in KEGG.

do I extrapolate right? where can I find a description of how these operators are defined? Thanks