P⁡{αβγa1b1c1za2b2c2}=(z-αz-γ)a1⁢(z-βz-γ)b1⁢P⁡{01∞00a1+b1+c1(z-α)⁢(β-γ)(z-γ)⁢(β-α)a2-a1b2-b1a1+b1+c2}.