Hi Miranda,

Specify a non-integer step size for y. e.g.

points = Table[If[(x - 1.1)^2 <= y, {x, y}, Nothing], {x, 1, 3}, {y, 0, 25, .1}] //
           Flatten[#, 1] &;
ListPlot[points]

The inequality can also be solved to get an exact solution for the range of y. e.g.

Reduce[(x - 11/10)^2 <= y && (x == 1 || x == 2 || x == 3) && y <= 25, y]
(* (x == 1 && 1/100 <= y <= 25) || (x == 2 && 81/100 <= y <= 25) || (x == 3 && 361/100 <= y <= 25) *)

Not sure what you mean by

I want to plot the convex hull of this mixed integer feasible region

Hello Rohit,

Thank you for your help. However, when I tried the Reduce function in my Mathematica, I got the error Reduce::ivar: 4 is not a valid variable, and output: Reduce[True, 4]. I also tried many other examples with Reduce function but got the same error. Do you know the reason I got such an error and how to fix it? Thank you so much!