46 citations · 80 across the 6 of their papers we have counts for
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math.QA2007★ 17 cited
Piecewise principal comodule algebras
Piotr M. Hajac, Ulrich Kraehmer, Rainer Matthes +1
A comodule algebra P over a Hopf algebra H with bijective antipode is called principal if the coaction of H is Galois and P is H-equivariantly projective (faithfully flat) over the…
math.DG2007★ 46 cited
Noncommutative Geometry Approach to Principal and Associated Bundles
Paul F. Baum, Piotr M. Hajac, Rainer Matthes +1
We recast basic topological concepts underlying differential geometry using the language and tools of noncommutative geometry. This way we characterize principal (free and proper)…