In this talk I shall discuss some regularities of many‐body systems in the presence of random interactions and regularities of a single‐j shell for the J
pairing interaction which works only when two particles are coupled to spin J. I shall first explain an empirical rule to predict the spin I
ground state probability. Then I shall present some interesting results of a single‐j shell under the J
pairing interaction. Last I shall discuss some preliminary results of binding energies in the presence of random two‐body interactions.