I have a question about notation. I have arrived at a matrix, the first two columns of which I'm labeling for future reference. I don't care about and won't be using the third column. It will be clear to the reader from the context I provide, but I'd like to know if there's a standard method of saying "ignore this column". What I'm using now is: $$\begin{bmatrix} | & | & |\\ \omega_1 & \omega_2 & \sim \\ | & | & | \\ \end{bmatrix}$$
Good enough? Just curious if there's a tried and true method in the math community.