Singular varieties and infinitesimal non-commutative Witt vectors

Phùng Hô Hai, João Pedro dos Santos, Đào Văn Thinh

Given a projective variety $X$ over an algebraically closed field $k$, M. V. Nori introduced in 1976 a group scheme $\pi (X)$ which accounts for principal bundles $P\to X$ with finite…