I have tried to link some topics in mathematics which included the word " Rational" , I have got many references which used " Rational" in Group theory and Probability and number theory and algebraic geometry and Topology,Chaos theory and so on , Now I'm confused and I have asked my self many times why that "Rational" occurs so much in all topics of mathematics probably informatic and physics ? Why this word interesting in mathematics ? According to the below linked reference I ask why always we investigate to get things in mathematics to be rational ?What is the special of that word rational in mathematics ?
**List of Linked reference include word " Rational"**:
[Regularization of Rational Group Actions](https://arxiv.org/abs/1808.08729)
[Rational Points on Rational Curves](https://arxiv.org/abs/1911.12551)
[Automatic sets of rational numbers](https://arxiv.org/abs/1110.2382)
[Rational homology 3-spheres and simply connected definite bounding](https://arxiv.org/abs/1808.09135)
[Rational Homotopy Theory](https://link.springer.com/book/10.1007/978-1-4613-0105-9)
[A Rational Informatics-enabled approach to the Standardised Naming of Contours and Volumes in Radiation Oncology Planning](https://www.academia.edu/7430350/A_Rational_Informatics-enabled_approach_to_the_Standardised_Naming_of_Contours_and_Volumes_in_Radiation_Oncology_Planning)
[Is Science Rational?](https://link.springer.com/chapter/10.1007/978-94-010-2115-9_36)
[A note on p-rational fields and the abc-conjecture](https://arxiv.org/abs/1903.11271)
[Remarks on rational vector fields on CP1](https://arxiv.org/abs/1909.09439)
[Rational Analysis](https://www.sciencedirect.com/topics/computer-science/rational-analysis)
[Rational probability measures](https://www.sciencedirect.com/science/article/pii/030439758990042X)
[A trace formula for the distribution of rational G-orbits in ramified covers, adapted to representation stability](https://arxiv.org/abs/1703.01710)
[Rational cobordisms and integral homology](https://arxiv.org/abs/1811.01433)
[Conditioned invariant subspaces, disturbance decoupling and solutions of rational matrix equations](https://www.tandfonline.com/doi/abs/10.1080/00207178608933450)
[Why study unirational and rational varieties?](https://mathoverflow.net/q/287364/51189)
[Degree of rational maps via specialization](https://arxiv.org/abs/1901.06599)
[Minimum rational entropy fault tolerant control for non-Gaussian singular stochastic distribution control systems using T-S fuzzy modelling](https://www.tandfonline.com/doi/abs/10.1080/00207721.2018.1526984)
[On the generic nonexistence of rational geodesic foliations in the torus, Mather sets and Gromov hyperbolic spaces](https://link.springer.com/article/10.1007/BF01377597)
[Irrationality Measure of Pi](https://arxiv.org/abs/1902.08817)
[Rational Unified Process](https://arxiv.org/abs/1609.07350)
[Rational Computations of the Topological K-Theory of Classifying Spaces of Discrete Groups](https://arxiv.org/abs/math/0507237)
[On Periodic and Chaotic Orbits in a Rational Planar System](https://arxiv.org/abs/1405.3124)
**Note** I do not investigate about the meaning of the word "Rational" in each topic but I want to know why its were dominated why it is interesting whatever the kind of its meaning ?