The class character rings of sporadic groups

The class character rings of sporadic groups have been found. For that we analysed character tables of sporadic groups from GAP. Also we determined those class character rings, which is trivial with respect to multiplication (class character ring is called trivial with respect to multiplication if it is ring of integers or subring of imaginary quadratic field). These results are initial steps towards description of central unit group of integral group rings of sporadic groups.