“…While our framework does not cover this SDP relaxation, it is not clear to us how to extend the SDP relaxed verifier to general nonlinearities, for example max-pooling, which can be done in our framework on the other hand. Other verifiers have been proposed to certify via an intermediary step of bounding the local Lipschitz constant [Hein and Andriushchenko, 2017, Weng et al, 2018, Raghunathan et al, 2018a, Zhang et al, 2019, and others have used randomized smoothing to certify with high-probability [Lecuyer et al, 2018, Li et al, 2018, Cohen et al, 2019, Salman et al, 2019. These are outside the scope of our framework.…”