Card payment fraud detection is usually framed as a supervised classification problem. Although this approach has generated practical progress, improvement has remained incremental despite major advances in model architecture. We argue that this is not mainly a failure of function approximation or optimization, but a consequence of structural information impairments inherent to the payment ecosystem. We formalize card authorization as a sequential decision problem with delayed, censored, corrupted, and counterfactually missing feedback. We derive a minimax regret lower bound showing that these impairments enter multiplicatively in the denominator of the achievable learning rate. The bound implies that improving issuer reporting quality or reducing censorship can yield larger reductions in the regret floor than increasing model complexity. We also show that heterogeneity across issuers worsens learnability beyond what average impairment rates suggest. The paper contributes a theory of why fraud detection in payment networks is fundamentally harder than in standard online learning settings, identifies ecosystem information quality as the key bottleneck, and provides a theoretical basis for prioritizing investments in reporting infrastructure, dispute process quality, and selective exploration. The paper is theory-first and does not rely on proprietary transaction data.

We introduce a semi-parametric Bayesian model for survival analysis. The model is centred on a parametric baseline hazard, and uses a Gaussian process to model variations away from it nonparametrically, as well as dependence on covariates. As opposed to many other methods in survival analysis, our framework does not impose unnecessary constraints in the hazard rate or in the survival function. Furthermore, our model handles left, right and interval censoring mechanisms common in survival analysis. We propose a MCMC algorithm to perform inference and an approximation scheme based on random Fourier features to make computations faster. We report experimental results on synthetic and real data, showing that our model performs better than competing models such as Cox proportional hazards, ANOVA-DDP and random survival forests.

'It was like a phone call suddenly connecting' Ai Weiwei. 'It was like a phone call suddenly connecting' Ai Weiwei. 'Was I scared going back to China? He has been jailed, tracked and threatened by China's government. What was it like pay a visit home?

Censorship has been a constant in Ai Weiwei's life. The 68-year-old Chinese dissident, whose activist art has made him among Beijing's most prominent critics, has seen his films, sculptures and other works restricted for their criticisms of China as well as his outspoken advocacy for human rights around the world. Speaking in London ahead of the January 29 launch of his new book On Censorship," he discussed returning to China for the first time in a decade, the impact of AI on freedom of expression, and what he sees as the erosion of free speech in the West. This conversation has been edited and condensed for clarity. In a time of both misinformation and too much information, quality journalism is more crucial than ever.

The people of Venezuela have spent years learning resilience in the face of censorship, disinformation, and repression. They now rely on those tools more than ever. In the early morning hours of Saturday, January 3, the roar of bombs dropping from the sky announced the US military attack on Venezuela, waking the sleeping residents of La Carlota, in Caracas, a neighborhood adjacent to the air base that was a target of Operation Absolute Resolve. Marina G.'s first thought, as the floors, walls, and windows of her second-story apartment shook, was that it was an earthquake. Her cat scrambled and hid for hours, while the neighbors' dogs began to bark incessantly.

Apple could unveil Gemini-powered Siri in Feb. California will investigate TikTok's alleged censorship of anti-Trump posts Users also complained about being unable to upload ICE-related videos, but TikTok is blaming issues on a power outage. California Governor Gavin Newsom has announced that his office is investigating whether TikTok is truly censoring content critical of Trump, days after ByteDance finalized a deal to spin off its business in the US. Newsom made the announcement in response to a post on X, claiming that you can no longer send messages in the app with the word "Epstein" in it. Newsom's office, in a separate post, said it was able to independently confirm instances wherein TikTok suppressed content critical of President Donald Trump.