Triple

Target class: discrete subgroup of PSL(2,R)
Context triple: [(2,3,7) triangle group, instanceOf, discrete subgroup of PSL(2,R)]

• A. pseudogroup
  A pseudogroup is a collection of local homeomorphisms (or diffeomorphisms) on a topological space that is closed under composition, inversion, restriction to open subsets, and gluing of compatible local maps, generalizing the notion of a group action to local symmetries.
• B. subgroup chosen
  A subgroup is a subset of a group that is itself a group under the same binary operation, containing the identity, inverses, and being closed under the operation.
• C. 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.
• D. finite simple group
  A finite simple group is a finite group that has no nontrivial normal subgroups, meaning its only normal subgroups are the trivial group and the group itself.
• E. automorphic representation (in a broad sense)
  An automorphic representation (in a broad sense) is an irreducible unitary representation of an adelic or locally compact group that arises in the spectral decomposition of spaces of automorphic forms, encoding number-theoretic and geometric information via harmonic analysis on arithmetic quotients.
• F. None of above.