What parametrization are you using ? And write the definitions you're working with. As per the guidelines of this particular forum, you're asked to post your work first and ask for advice/help later.
And this looks like pure mathematics subject, why did you place it here ?
Now I know that left invariant vector fields are obtained starting from vector tanget to the identity of the group (pauli matrices).
by duality i can find also a basis for the left invariant forms.
a) Is this right?
Once I've found the left invariant forms [itex]θ^{i}[/itex]
I can define the metric g=[itex]g_{\mu\nu}[/itex][itex]θ^{\mu}\otimesθ^{\nu}[/itex]
b)Is this the left invariant metric I'm looking for? Are the metric coefficient totally arbitrary, a part the constraints to make the metric non degenerate and strictly positive (if i want a riemannian metric)?
I'm sorry if this is not the the right place for my post! Thank you for helping!