we are given the following constraints for x $$x \le e+f-a$$ $$x \le z+f-c$$ $$x \le e+y-b$$ $$d \le b+c-a$$
We need to prove(or disprove) that
$$x \le z+y-d$$ where $x, y, z, a, b, c, d, e \in \mathbb{R}$ I tried for some examples and it seems that the relation to be shown holds given the constraints. But I don't know the formal way of proving. Any starting point, hint will be helpful.