Triple

Target class: modular form
Context triple: [Eisenstein series, instanceOf, modular form]

• A. endomorphism of modular forms space
  An endomorphism of a modular forms space is a linear self-map of a given space of modular forms (typically of fixed weight, level, and character) that sends each modular form in the space to another modular form in the same space.
• B. modular function chosen
  A modular function is a complex-valued function on the upper half-plane that is invariant under the action of a modular group (typically SL(2,ℤ)) and is meromorphic on the extended upper half-plane, including at the cusps.
• C. 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.
• D. L-function
  An L-function is a complex analytic function, typically expressed as a Dirichlet series with an Euler product, that encodes deep arithmetic information about objects such as numbers, fields, or algebraic varieties.
• E. even unimodular lattice
  An even unimodular lattice is a free abelian group of finite rank equipped with a positive-definite symmetric bilinear form whose Gram matrix has determinant 1 and for which the squared length of every lattice vector is an even integer.
• F. None of above.