# Qiskit gates in LaTeX representation: notation meaning [duplicate]

I started working in Qiskit, and here is an example of how gates of a circuit are represented graphically in LaTeX format:

Obviously, $$R_y(\theta)$$, is a y rotation by a certain angle. But all the other gates look like $$U_i(x,y,z)$$, and I don't know how what they actually do. What is their matrix representation? What do the numbers $$i,x,y$$ and $$z$$ mean?