This eliminates the need to generate resonance structures, and both positive and negative results can be determined by comparing a single pair of structures. This new approach can identify identical molecules more reliably than strict isomorphism because it avoids any limitations in the resonance generation algorithm. For example, prior to the implementation of an algorithm for benzyne resonance, loose isomorphism could correctly identify the two resonance structures of benzene as being the same molecule while strict isomorphism could not. The timing for this method is shown by the second (orange) bar in Figure . We see that this method is almost identical in performance to normal isomorphism, with the main difference being faster identification of different molecules with many resonance structures, as demonstrated by Test 5. Additionally, there is a guaranteed performance improvement because resonance structure generation is avoided.