Hello all,

I am trying to model this problem:

x is a positive and nonzero parameter, y is a continuous and nonnegative variable, and z is a binary variable. I'd like to model this nested condition:

1- if y=0 then z=0

2- if y>0, then if x<=y then z=0, but if x>y then z=1.

I tried to use a big M method like this: x<= y+bigm*z but since z is nonzero when y=0 I get infeasibility.

I appreciate any help or idea on modeling this problem.

Thanks,

Yar