|A+B|=|α+β, (1+λ)γ1, (1+μ)γ2|=|α, (1+λ)γ1, (1+μ)γ2| +|β,(1+λ)γ1,(1+μ)γ2|
=(1+λ)(1+μ)|α,γ1,γ2|+(1+λ)( 1+μ)|β, γ1, γ2|=(1+λ)(1+μ)(a+b)
|A+B|=|α+β, (1+λ)γ1, (1+μ)γ2|=|α, (1+λ)γ1, (1+μ)γ2| +|β,(1+λ)γ1,(1+μ)γ2|
=(1+λ)(1+μ)|α,γ1,γ2|+(1+λ)( 1+μ)|β, γ1, γ2|=(1+λ)(1+μ)(a+b)