4-Books of three pages

Let HH be a 4-uniform hypergraph on an n  -element vertex set VV containing no 4-book of 3 pages, i.e., a hypergraph of 4 quadruples with vertices {1,2,…,7}{1,2,…,7} and edges {1234,1235,1236,4567}{1234,1235,1236,4567}. Then for n>n0n>n0e(H)⩽⌊n/2⌋2⌈n/2⌉2.Moreover, here equality is possible only if V(H)V(H) can be partitioned into two sets A and B   so that each quadruple of HH intersects A (and B) in exactly two vertices.