Even training a linear classifier is NP-hard to approximate, notes Aaron Roth

Aaroth · x · 2026-09-14

In his thread, Aaron Roth gives a concrete example: the simplest ML problem — learning a linear classifier that minimizes classification error — is NP-hard even to approximate (distinguishing 51% from 99% accuracy), and everything more general is at least as hard. This is part of his argument that worst-case complexity theory is a poor guide to what is achievable in machine learning.

Related event: Aaron Roth Slams Complexity-Based Arguments Against AI(4 posts)→

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