  Covariance of a quantum space with respect to a quantum enveloping algebra
ties the deformation of the multiplication of the space algebra to the
deformation of the coproduct of the enveloping algebra. Since the deformation
of the coproduct is governed by a Drinfeld twist, the same twist naturally
defines a covariant star product on the commutative space. However, this
product is in general not associative and does not yield the quantum space. It
is shown that there are certain Drinfeld twists which realize the associative
product of the quantum plane, quantum Euclidean 4-space, and quantum Minkowski
space. These twists are unique up to a central 2-coboundary. The appropriate
formal deformation of real structures of the quantum spaces is also expressed
by these twists.
