In mathematics, Tate duality or Poitou–Tate duality is a duality theorem for Galois cohomology groups of modules over the Galois group of an algebraic number field or local field, introduced by Tate (1962) and Poitou (1967).
Local Tate duality
Local Tate duality says there is a perfect pairing of finite groups
where M is a finite group scheme and M′ its dual Hom(M,Gm).
References
Tate duality Wikipedia(Text) CC BY-SA