考慮兩個有限維不可分解的sl(n)-module 之張量積。Weyl′s Theorem 保證我們可以將該張量積拆解成很多不可分解的子結構之直和。其中,我們將發現, 直和中各項的係數其實就是有名的Littlewood-Richardson coe fficients。;Consider the tensor product of two finite dimensional irreducible sl(n)-modules. By Weyl′s Theorem, we can decompose the tensor product into a direct sum of irreducible sl(n)-submodules. We will prove that the coeff icients in the decomposition are actually the well-known Littlewood-Richardson coeff icients.