Как по Английски будет pfaffian

noun

Any of various mathematical objects occurring in or derived from the work of pfaff on differential equations. originally: specifically (a. cayley's term for) a function involving permutations arising from this work.

adjective

Of or relating to (mathematical objects occurring in) the work of pfaff; specifically designating a differential equation of the form f₁ d x₁ +…+ fₙ d xₙ = 0, where each fᵢ is a function of the variables xᵢ.