\* Problem: Unknown *\

Minimize
 obj: - x_1 - x_2

Subject To
 r_1: + 2 x_2 + x_1 - ~r_1 = 0
 r_2: + x_2 + x_1 - ~r_2 = -1
 r_3: - 1e+016 x_3 + x_1 <= 0
 r_4: - 1e+016 x_4 + x_2 <= 0
 r_5: + 1e+016 x_3 + x_1 >= 0
 r_6: + 1e+016 x_4 + x_2 >= 0
 r_7: + x_4 + x_3 = 1

Bounds
 0 <= ~r_1 <= 1
 0 <= ~r_2 <= 2
 0 <= x_1 <= 0.0005
 0 <= x_2 <= 1
 0 <= x_3 <= 1
 0 <= x_4 <= 1

Generals
 x_3
 x_4

End