description of the hypernuclear matter. We found that the EOS of the hypernuclear matter is much softer than that of the pure nuclear matter, and that it becomes even softer if the hadron-quark phase transition is included. The masses and radii of hybrid stars were also studied with these EOSs, and they were found to remain rea- sonable after including hyperons and the hadron-quark phase transition. We have also studied the effects of at- tractive and repulsive ΣN interactions and different sym- metry energies on the hybrid star properties. The results show that the appearance of the Σ hyperon in hybrid stars depends sensitively on the sign of the ΣN interac- tion with a repulsive ΣN interaction giving a higher criti- cal density for the appearance of Σ hyperons. In addition, a stiffer symmetry energy usually leads to a larger frac- tion of hyperons in the hypernuclear matter. We further found that both the low-density boundary of the hadron- quark phase transition and the EOS at high densities in hybrid stars are more sensitive to the bag constant than to the stiffness of the nuclear symmetry energy at high densities. This extended MDI interaction, which gives an isospin- and momentum-dependent in-medium effec- tive interactions for the baryon octet, will also be very 

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## Acknowledgments 

