The physical interpretation of the basic concepts of the theory of cov
ariant groups - coproducts, representations and corepresentations, act
ion and coaction - is discussed for the examples of the simplest q def
ormed objects (quantum groups and algebras, q oscillators, and comodul
e algebras). It is shown that the reduction of the covariant algebra o
f quantum second-rank tensors includes the algebras of the q oscillato
r and quantum sphere. A special case of covariant algebra corresponds
to the braid group in a space with nontrivial topology.