2 problems

A knot has a Lissajous projection if its projection to the $x$-$y$ plane arises from a second-order Lissajous parametrization, with coordinates of the form … for integer frequencie…

A second-order Lissajous knot is a knot $K$ represented parametrically by … … where $n_1,n_2,n_3,n_4$ are integer frequencies, $\phi_1,\phi_2,\phi_3,\phi_4$ are real phase shifts,…