We show that for any large n, there exists a set of n points in the plane with O(n²/√log n) distinct distances, such that any four points in the set determine at least five distinct distances. This answers (in the negative) a question of Erd{o}s. The proof combines an analysis by Dumitrescu of forbidden four-point patterns with an algebraic construction of Thiele and Dumitrescu (to eliminate parallelograms), as well as a randomized transformation of that construction (to eliminate most other forbidden patterns).
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Terence Tao (2024) studied this question.
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