Terms containing the key tools

Subject	English	Russian
math.	the key tool in the proof of Theorem 1 are asymptotic existence theorems which were proved in 4	центральное орудие
math.	the key tools	ключевое орудие (in the proof of Theorem 1 are ...)
math.	the key tools in the proof of Theorem 1 are asymptotic existence theorems 3	основным средством в доказательстве