On 3‐graphs with no four vertices spanning exactly two edges

Let D 2 $D_2$ denote the 3-uniform hypergraph with 4 vertices and edges. Answering a question of Alon Shapira, we prove an induced removal lemma for having polynomial bounds. We also Erdős–Hajnal-type result: Every -free on n $n$ contains clique or independent set size c $n^{c}$ some absolute constant > 0 $c 0$ . In case both problems, is only nontrivial k $k$ -uniform ⩾ 3 $k\geqslant 3$ which admits bound.