Clique in 3-track interval graphs is APX-hard

Butman, Hermelin, Lewenstein, and Rawitz proved that Clique in t-interval graphs is NP-hard for t >= 3. We strengthen this result to show that Clique in 3-track interval graphs is APX-hard

Clique in 3-track interval graphs is APX-hard ∗

Butman, Hermelin, Lewenstein, and Rawitz proved that CLIQUE in t-interval graphs is NP-hard for t ≥ 3. We strengthen this result to show that CLIQUE in 3-track interval graphs is APX-hard