@article {2008, title = {The Isospectral Dirac Operator on the 4-dimensional Orthogonal Quantum Sphere}, journal = {Comm. Math. Phys. 279 (2008) 77-116}, number = {SISSA;95/2007/MP}, year = {2008}, abstract = {Equivariance under the action of Uq(so(5)) is used to compute the left regular and (chiral) spinorial representations of the algebra of the quantum Euclidean 4-sphere S^4_q. These representations are the constituents of a spectral triple on this sphere with a Dirac operator which is isospectral to the canonical one of the spin structure of the round undeformed four-sphere and which gives metric dimension four for the noncommutative geometry. Non-triviality of the geometry is proved by pairing the associated Fredholm module with an {\textquoteleft}instanton\\\' projection. A real structure which satisfies all required properties modulo a suitable ideal of {\textquoteleft}infinitesimals\\\' is also introduced.}, doi = {10.1007/s00220-008-0420-x}, url = {http://hdl.handle.net/1963/2567}, author = {Francesco D{\textquoteright}Andrea and Ludwik Dabrowski and Giovanni Landi} }