On a conjecture of Danzer and Grünbaum
On a conjecture of Danzer and Grünbaum
The main result of the paper is that if <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper A"> <mml:semantics> <mml:mi>A</mml:mi> <mml:annotation encoding="application/x-tex">A</mml:annotation> </mml:semantics> </mml:math> </inline-formula> is a family of homothetic triangles in the plane such that any 9 of them can be pierced by two points, then all members of <inline-formula content-type="math/mathml"> <mml:math …