US Patent 7391234 Circuit and circuit connecting method

A network structure configures a blocking network having constraint against such a combination of said network input terminal and network output terminal as to make it unfeasible to further connect, when connecting first network input terminals to first network output terminals, second network input terminals to any one of the second network output terminals, and operation elements and the network output terminals are connected so as to minimize a constraint strength between the plurality of network output terminals inputting to the same operation element with respect to the constraint strength defined as the number of network input terminals contained in tuples of network input terminals to which the two network output terminals in the network output terminals can not be simultaneously connected.