宇宙無毛猜想推論均勻、均向的宇宙是必然的演化結果，亦即所有正宇宙常數的膨脹宇宙都會逐漸逼近均勻、均向的 de Sitter 時空。這個推論已經得到部分的證明和部份特例的支持。
這篇論文將分析、探討一個特別的 Bianchi typeⅠ 模型，對宇宙無毛猜想所提供的支持與證明。論文中會加入曲率張量二次項到 Einstein-Hibert 作用量中，用以修正 Einstein 方程式，並推算 Bianchi typeⅠ 模型一組不均向解，和一組 de Sitter 解。最後再以微擾的穩定性分析方法，證明這個不均向解是不穩定的，由此證明這個 Bianchi typeⅠ 模型的演化結果，還是會符合宇宙無毛猜想的推論。

Cosmic no-hair conjecture states that all expanding universe models with positive cosmological constant asymptotically approach the homogenous and isotropic de Sitter solution. This conjecture has been proved under certain energy conditions and has also been supported by a number of expanding solutions realized for a few known models.

We will study the evolution of a homogeneous Bianchi typeⅠmodel which provides a supporting evidence of the comic no-hair conjecture. This model modifies the Einstein’s equation by the inclusion of quadratic curvature terms. Anisotropic solutions will be solved along with another de Sitter solution. The anisotropic solution can be shown to be unstable by a perturbation method. The result provides a positive supporting evidence for the comic no-hair conjecture.

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