Eq1 = p1*u12*x11 + h1*v12*D11 - f12*y11;
Eq2 = h1*v12*D11 - s1*u12*x11;
Eq3 = b*g32*a31 + (1 - h2)*v12*D11 - s2*u12*x11;
Eq4 = p2*u22*x21 + h2*v22*D21 - f22*y21;
Eq5 = h2*v22*D21 - s2*u22*x21;
Eq6 = x11 - (-p1*y11 - s1*a11 - s2*a31);
Eq7 = x21 - (1 - p2*y21 - s2*a21);
Eq8 = D11 - (h1*(y11 - a11) + (1 - h2)*(y21 - a21 - a31));
Eq9 = D21 - ((1 - h1)*(y11 - a11) + h2*(y21 - a21 - a31));
9 Unknowns: x11, x21, y11, y21, a11, a21, a31, D11, D21
We KNOW about the coefficient properties:
Questions: based on all the information, how to determine the signs of the 9 solutions? I was able to use mathematica to solve the equations and get the solutions which are VERY MESSY. then i don't know how to sign them (using what kind of syntax/code?), although i know they are signABLE.
of course, this problem can be downgraded to a 5-equation system, but i doubt that helps a lot.
Thanks for your help.