This is a detailed review of the AI system AlphaTensor, developed by DeepMind and published in Nature in 2021. The model uses deep learning to play a novel game called TensorGame, designed to find optimal algorithms for matrix multiplication. It automatically discovers several state-of-the-art algorithms for small-sized matrices and improves on previously known ones. AlphaTensor demonstrates that AI systems can independently discover new mathematical concepts, a feat hitherto accomplished by human mathematicians alone.