[**Remarks on DSR and Gravity**]{}

[F. Hinterleitner]{}

[*Institute of Theoretical Physics and Astrophysics,\
Faculty of Science of the Masaryk University,\
Kotlářská 2, 611 37 Brno, Czech republic*]{}

Modifications of Special Relativity by the introduction of an invariant energy and/or momentum level (so-called Doubly Special Relativity theories, DSR) or by an energy-momentum dependence of the Planck constant (Generalized Uncertainty Principle, GUP) are compared with classical gravitational effects in an interaction process. For the low energy limit of the usual formulations of DSR to be equivalent to Newtonian gravity, a restrictive condition is found. GUP yields an effective repulsion, in analogy to gravitational repulsion in loop quantum cosmology.

Introduction
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Tentative quantum theories of gravity – string theory as well as loop quantum gravity or non-commutative geometry – indicate the existence of an invariant length scale of the order of magnitude of the Planck length, which is in obvious contradiction with standard Lorentz symmetry, when taken seriously to arbitrary small scales. For this reason in the last years various attempts were made to modify Special Relativity (SR) [@GAC; @MS] in such a way that one (or more) invariant quantities in addition to the speed of light would be reconciled with the relativity 