TY - JOUR AU - Amini, Omid TI - The exchange graph and variations of the ratio of the two Symanzik polynomials JO - Annales de l’Institut Henri Poincaré D PY - 2019 SP - 155 EP - 197 VL - 6 IS - 2 UR - http://archive.numdam.org/articles/10.4171/aihpd/68/ DO - 10.4171/aihpd/68 LA - en ID - AIHPD_2019__6_2_155_0 ER -