Triple

Target class: Galois cohomology group
Context triple: [Shafarevich group of a torus, instanceOf, Galois cohomology group]

• A. cohomological invariant
  A cohomological invariant is a rule that assigns to each object in a given class (such as algebraic varieties, groups, or topological spaces) an element of a cohomology group in a way that is functorial and captures structural or classification information about those objects.
• B. group (mathematics) chosen
  A group is a set equipped with a single binary operation that is closed, associative, has an identity element, and in which every element has an inverse.
• C. linear algebraic group
  A linear algebraic group is a group that is also an affine algebraic variety, whose group operations (multiplication and inversion) are given by regular polynomial maps when the group is realized as a closed subgroup of some general linear group GLₙ.
• D. cohomology theory
  A cohomology theory is a functorial assignment of graded algebraic invariants to topological spaces (or other mathematical objects) that encodes global structural and obstruction information via axioms such as exactness and homotopy invariance.
• E. representation of a group
  A representation of a group is a homomorphism from that group into the group of linear transformations of a vector space, allowing the group’s abstract elements to be studied via concrete matrices or operators.
• F. None of above.