Buckingham's p theorem

Buckingham's π theorem [′bək·iŋ·əmz ′pī ‚thir·əm]

(physics)

The theorem that if there arenphysical quantities,x₁,x₂, …,x_n, which can be expressed in terms ofmfundamental quantities and if there exists one and only one mathematical expression connecting them which remains formally true no matter how the units of the fundamental quantities are changed, namely φ(x₁,x₂, …,x_n) = 0, then the relation φ can be expressed by a relation of the formF(π₁, π₂, …, π_n-m) = 0, where the πs aren-mindependent dimensionless products ofx₁,x₂, …,x_n. Also known as pi theorem.