(Three points theorem) For a curve γ, the set { {q1, q2} | q1, q2∈γ, q1+q2+q3= 0 } for a given q3∈γ is equal to the set { {q, q*} |q∈γ∩γ'} where γ' = {-q-q3 | q∈γ} is an inversion and parallel translation of the curve γ, and q* =−q−q3.
The theorem states that for a curve γ and for a given q3 ∈γ, if there is a pair q1, q2 ∈γ that satisfy q1+q2+q3= 0 then the points q1 and q2 should be the cross points of γ and γ'. In the following animations, black curve represents γ and red γ'.
Circular or Eliptic choreography
Circular or Eliptic choreography
Figure-eight choreography
Figure-eight choreography
Lemniscate
Lemniscate
Newtonian gravity
Newtonian gravity
Lennard-Jones potential
Lennard-Jones potential
(All animations above made of 720 frames per period and each frame spends 40msec.)