Roth translates Kron’s "orthogonality conditions" into exact sequences of homology or cohomology. Roth’s interpretation is confirmed by Raoul Bott in reports in Mathematical Reviews. Roth says, "tearing consists essentially in deducing from the solution of one (easier to solve) network K~ the solution of a network K having the same number of branches as K~ and having the same isomorphism L between the groups of 1-chains and 1-cochains."