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It is stated that holonomy corrections in loop quantum cosmology introduce amodification in Friedmann's equation which prevent the big rip singularity.Recently in \cite{h12} it has been proved that this modified Friedmann equationis obtained in an inconsistent way, what means that the results deduced fromit, in particular the big rip singularity avoidance, are not justified. Theproblem is that holonomy corrections modify the gravitational part of theHamiltonian of the system leading, after Legendre's transformation, to a noncovariant Lagrangian which is in contradiction with one of the main principlesof General Relativity. A more consistent way to deal with the big ripsingularity avoidance is to disregard modification in the gravitational part ofthe Hamiltonian, and only consider inverse volume effects \cite{bo02a}. In thiscase we will see that, not like the big bang singularity, the big ripsingularity survives in loop quantum cosmology. Another way to deal with thebig rip avoidance is to take into account geometric quantum effects given bythe the Wheeler-De Witt equation. In that case, even though the wave packetsspread, the expectation values satisfy the same equations as their classicalanalogues. Then, following the viewpoint adopted in loop quantum cosmology, onecan conclude that the big rip singularity survives when one takes into accountthese quantum effects. However, the spreading of the wave packets prevents therecover of the semiclassical time, and thus, one might conclude that theclassical evolution of the universe come to and end before the big rip isreached. This is not conclusive because. as we will see, it always exists otherexternal times that allows us to define the classical and quantum evolution ofthe universe up to the big rip singularity.

Does loop quantum cosmology replace the big rip singularity by a non-singular bounce?