Ladder operators for Chebyshev-Koornwinder oscillator

We obtain differential expressions for ladder operators of generalized oscillator related to the bivariate Chebyshev-Koornwinder (CK) polynomials. Using the representation of differential operators of Koornwinder by “number operators” of CK-oscillator, we get a completion of Koornwinder algebra. This extension is an Abelian subalgebra of CK-oscillator algebra.