Hello everyone, I am trying to solve these two errors but I can’t. Can you please help me? thanks.

Btw, here’s the code.

Sets

i ‘materials purchased from outside (raw material, shaft, chest, motor’ /1,2,3,4/

j ‘components produced by the company itself (assembly time)’ /1,2,3/ ;

Parameters

c(i) delivery time /c1 10, c2 7, c3 5, c4 15/

d(j) assembly time /d1 3, d2 4, d3 6/

S(i) stock capacity /S1 100, S2 80, S3 50, S4 30/

M(j) minimum assembly time /M1 2, M2 3, M3 5/

Tmax maximum supply time /Tmax 30/;

Variables

x(i) Quantities to be kept in stock

y(j) Assembly time of the company’s own manufactured components

T Total supply time

Positive Variable x,y;

Free Variable T;

Equations

objective_ objective function value to be minimized

stock_constraints(i) limiting stocks to maximum capacity

assembly_time_constraints(j) assembly time constraints

supply_time_constraint supply time constraints;

objective_… T =e= sum(i, c(i)*x(i)) + sum(j, d(j)*y(j));

stock_constraints(i)… x(i) =l= S(i);

assembly_time_constraints(j)… y(j) =g= M(j);

supply_time_constraint… T =l= Tmax;

Model supply_model /all/;

Solve supply_model using lp minimizing T;