We determine the complete set of generalized spin squeezing inequalities, given in terms of the collective angular momentum components, for particles with an arbitrary spin. They can be used for the experimental detection of entanglement in an ensemble in which the particles cannot be individually addressed. We also present a complete set of criteria involving collective observables different from the angular momentum coordinates. We also discuss how our inequalities distinguish between inter-particle and intra-particle squeezing, which is needed for entanglement conditions for particles with a spin larger than 1/2. Our findings are especially useful in the light of recent experiments with spinor condensates and spin nematics.
 G. Vitagliano, P. Hyllus, I.L. Egusquiza, and G. Tóth, Spin squeezing inequalities for arbitrary spin, Phys. Rev. Lett. 107, 240502 (2011).