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Causality Without Causal Models

Halpern, Joseph Y., Pass, Rafael

arXiv.org Artificial Intelligence

Perhaps the most prominent current definition of (actual) causality is due to Halpern and Pearl. It is defined using causal models (also known as structural equations models). We abstract the definition, extracting its key features, so that it can be applied to any other model where counterfactuals are defined. By abstracting the definition, we gain a number of benefits. Not only can we apply the definition in a wider range of models, including ones that allow, for example, backtracking, but we can apply the definition to determine if A is a cause of B even if A and B are formulas involving disjunctions, negations, beliefs, and nested counterfactuals (none of which can be handled by the Halpern-Pearl definition). Moreover, we can extend the ideas to getting an abstract definition of explanation that can be applied beyond causal models. Finally, we gain a deeper understanding of features of the definition even in causal models.


Hardness of Online Sleeping Combinatorial Optimization Problems

Satyen Kale, Chansoo Lee, David Pal

Neural Information Processing Systems

We show that several online combinatorial optimization problems that admit efficient no-regret algorithms become computationally hard in the sleeping setting where a subset of actions becomes unavailable in each round. Specifically, we show that the sleeping versions of these problems are at least as hard as P AC learning DNF expressions, a long standing open problem.





A Model, training, and dataset details All models are trained end-to-end with the Gumbel-Softmax [

Neural Information Processing Systems

Models are trained on a single Titan Xp GPU on an internal cluster. Training time is typically 6-8 hours on 4 CPUs and 32GB of RAM. We train with batch size B = 128 . Like ShapeWorld, RNN encoders and decoders are single layer GRUs with hidden size 1024 and embedding size 500. For additional example games from both datasets, see Figure S1.





Verifying rich robustness properties for neural networks

Afzal, Mohammad, Akshay, S., Gupta, Ashutosh

arXiv.org Artificial Intelligence

Robustness is a important problem in AI alignment and safety, with models such as neural networks being increasingly used in safety-critical systems. In the last decade, a large body of work has emerged on local robustness, i.e., checking if the decision of a neural network remains unchanged when the input is slightly perturbed. However, many of these approaches require specialized encoding and often ignore the confidence of a neural network on its output. In this paper, our goal is to build a generalized framework to specify and verify variants of robustness in neural network verification. We propose a specification framework using a simple grammar, which is flexible enough to capture most existing variants. This allows us to introduce new variants of robustness that take into account the confidence of the neural network in its outputs. Next, we develop a novel and powerful unified technique to verify all such variants in a homogeneous way, viz., by adding a few additional layers to the neural network. This enables us to use any state-of-the-art neural network verification tool, without having to tinker with the encoding within, while incurring an approximation error that we show is bounded. We perform an extensive experimental evaluation over a large suite of 8870 benchmarks having 138M parameters in a largest network, and show that we are able to capture a wide set of robustness variants and outperform direct encoding approaches by a significant margin.