# Generic instabilities of nonsingular cosmologies in Horndeski theory: A no-go theorem

@article{Kobayashi2016GenericIO, title={Generic instabilities of nonsingular cosmologies in Horndeski theory: A no-go theorem}, author={Tsutomu Kobayashi}, journal={Physical Review D}, year={2016}, volume={94}, pages={043511} }

The null energy condition can be violated stably in generalized Galileon theories, which gives rise to the possibilities of healthy nonsingular cosmologies. However, it has been reported that in many cases cosmological solutions are plagued with instabilities or have some pathologies somewhere in the whole history of the universe. Recently, this was shown to be generically true in a certain subclass of the Horndeski theory. In this short paper, we extend this no-go argument to the full…

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