Question: Solve system of equations and inequalities with symbolic parameters

Hi guys,

I would like to solve a system of equations and inequalities with symbolic parameters (D, E, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z) for several variables (a, b, c, d, e, f, i, j, l, m, n, p, q, r, s, t, u, v).

Unfortunately the command below does not work. I get the message "Warning, solutions may have been lost".

"Solve({ l-u=0, m-v=0, n-u=0, p-v=0, Y+q-u=0, Y+r-v=0, Z+s-u=0, Z+t-v=0, (a-P*M)*l=0, (b-Q*M)*m=0,               (c-R*N)*n=0, (d-S*N)*p=0, (e-T*O)*q=0, (f-T*O)*r=0,  (i-T*E)*s=0,(j-T*E)*t=0, l>=0, m>=0, n>=0,p>=0, q>=0, r>=0, s>=0, t>=0,u>=0,v>=0, a>=0, b>=0,c>=0, d>=0, e>=0, f>=0, i>=0, j>=0, a-P*M<=0, b-Q*M<=0,               c-R*N<=0, d-S*N<=0, e-T*O<=0, f-T*O<=0, i-T*E<=0,j-T*E<=0, D-a-c-e-i=0, S-b-d-f-j=0}, 

{a,b,c,d,e,f,i,j,l,m,n,p,q,r,s,t,u,v,M,N,O,E,P,Q,R,S,T,U,V,W,X,Y,Z,D,S});"

I would be very happy if someone could help me with this."

Thank you very much!