zeros r c is a matrix with r rows and c columns filled with zeros

identity n is the identity matrix of dimension n

matrix equality

matrix addition

matrix multiplication

matrix transposition

row_add ~coeff i j m adds to the i-th row, the j-th row times coeff in m

row_swap i j m swaps the i-th and j-th rows of m

row_mul coeff i m multiplies the i-th row by coeff in m

filter_cols f m removes the columns of m whose index does not satisfy f

splits matrix m into the first n columns and the rest, producing two matrices