Appears in collection : Combinatorics and Arithmetic for Physics: special days

There exists a way, based on the notion of Quantum Doubles, to introduce analogs of partial derivatives on the so-called Reflection Equation algebras. Analogously to the classical case it is possible to use these ”q-derivatives” for different applications. I plan to explain their utility for constructing q-analogs of the Casimir operators, close to them cut-and-join operators, and the Capelli identity.