About 10 years ago, S.L. Woronowicz recognized that
quantum $SU(1,1)$ does not exist as a locally compact quantum
group. But research done by L.I. Korogodsky in 1994
and more recently, by Woronowicz suggests heavily that
an extension $\widetilde{SU}(1,1)$ of $SU(1,1)$ can be
deformed into a genuine locally compact quantum group.
Through the use of $q$-special functions, Erik Koelink
and the speaker showed in the first half of this year
that this is indeed the case. In this talk, we will
first look at the construction of this new locally
quantum group. In a last part, the quantized universal
enveloping Lie algebra and its precise action on the
canonical Hilbert space of quantum
$\widetilde{SU}(1,1)$ will be the focus of our
attention.