Sl. Woronowicz et S. Zakrzewski, QUANTUM DEFORMATIONS OF THE LORENTZ GROUP - THE HOPF ASTERISK-ALGEBRALEVEL, Compositio mathematica, 90(2), 1994, pp. 211-243
Three properties characteristic for the Lorentz group are selected and
all quantum groups with the same poperties are found. As a result, a
number of one, two and three parameter quantum deformations of the Lor
entz group is discovered. The deformations described in [1] and [2] ar
e among them. Only the Hopf -algebra level is discussed.