Source: cirosantilli/unitary-group
= Unitary group
{tag=Isometry group}
{wiki}
= $U(n)$
{synonym}
{title2}
<Group (mathematics)> of the <unitary matrices>.
<complex number>[Complex] analogue of the <orthogonal group>.
One notable difference from the orthogonal group however is that the unitary group is connected "because" its determinant is not fixed to two disconnected values 1/-1, but rather goes around in a continuous <unit circle>. $U(1)$ \i[is] the unit circle.