In this paper, we have studied Bianchi type-I string cosmological model by combining Kaluza-Klein (KK) theory and theory of gravity which is an extension of 5-dimensional KK string cosmological models. We have used equation of state in the form of p-string or Takabayasi string given by , where and denote the rest density of energy cloud of strings, and the tension density of the system of strings, respectively and is a constant. In order to get physically significant and viable solution various forms of the function are assumed, in this paper we assume (e.g. Astashenok et al. (2017) ), where is real number. Some physical and geometrical properties of the model are also discussed.

中文翻译：

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f(R)引力理论中的高维Bianchi I型弦宇宙学模型


本文结合Kaluza-Klein（KK）理论和引力理论研究了Bianchi I型弦宇宙学模型，它是5维KK弦宇宙学模型的扩展。我们使用了 p 弦或 Takabayasi 弦形式的状态方程，由 给出，其中 和 分别表示弦能量云的静止密度和弦系统的张力密度，并且 是一个常数。为了获得物理上有意义且可行的解决方案，假设了函数的各种形式，在本文中我们假设（例如 Astashenok 等人（2017）），其中 是实数。还讨论了模型的一些物理和几何特性。