Differential calculi on quantum principal bundles in the Ðurđević approach

In this thesis we study the Ðurđević theory of differential calculi on quantum principal bundles within the domain of noncommutative geometry. Throughout the exposition, an algebraic approach based on Hopf algebras is employed. We begin by briefly recalling the foundational concepts of Hopf algebras and comodule algebras. Hopf-Galois extensions are introduced, along with an important correspondence result which relates crossed product algebras and cleft extensions. Differential calculus over algebras is reviewed, with a particular focus on the covariant case. The Ðurđević theory is presented in a modern language. We compare this theory to existing literature on the topic. We extend the Ðurđević theory and provide explicit realisations of quantum principal bundles and complete differential calculi on the noncommutative algebraic 2-torus, the quantum Hopf fibration and on crossed product algebras, resulting in an original contribution within this thesis.