Inner estimation of the united solution set of interval linear algebraic system

We will denote intervals and interval vectors by Latin letters a, b, e . . . . (with or without index), interval matrices by capital Latin letters A, B, C , . . . Real vectors and matrices will be denoted by Latin letters with lower dots q, .b,e.,..., A., B., C . , . . . Endpoints of intervals and of interval vectors will be denoted by a_, ~ (lower and upper endpoims, respectively), real n u m b e r s b y Greek letters c~,fl, % . . . , and also by small Latin letters with lower dots or with bars. Let us consider a real system of linear equations