suppose both $x_{i,j}^{ab}$ and $y_{i,j}^a$ are binaries. Then how to rewrite the following if-then in linear form? $\sum_b x_{i,j}^{ab} \ge 1 \implies \sum_{i,j} y_{i,j}^a = 0$ I was thinking of considering an indicator. But is there a better way to not have any additional variables(indicators) ...