Sidon Subsets of (4,5)-Sets

Exact obstruction to extending the Ma--Tang 14-set with h=8

Let A be the seeded 14-point Ma--Tang set. I checked that it has exactly 143 Sidon 8-subsets. For a Sidon 8-subset S, adjoining x fails to produce a Sidon 9-set exactly when a new sum collides: x+s=p+…