Reviews: A Non-generative Framework and Convex Relaxations for Unsupervised Learning

The introduction claims that this approach to unsupervised learning removes generative assumptions that have been common in the area. I do agree that the unified formulation has many desirable properties, including the notion of excess risk and the lack of assumptions on the data generating process. However, for the PSCA problem, the paper does make a generative assumption, namely the regularly spectral decodable assumption. And for the dictionary learning problem, the paper changes the formulation somewhat substantially to allow for group encoding/decoding. So the paper fails to provide strong evidence supporting the unified view of unsupervised learning through CONUS-learnability.