Triple

Target class: factorization system
Context triple: [Freyd–Kelly factorization system, instanceOf, factorization system]

• A. decomposition theorem
  The decomposition theorem is a fundamental result in algebraic geometry and topology stating that, under suitable conditions, the direct image of an intersection complex under a proper map splits as a direct sum of shifted semisimple perverse sheaves.
• B. fibration
  A fibration is a structure-preserving map between spaces (often in topology or category theory) that behaves like a fiber bundle, allowing one to consistently view the domain as being “fibered” over the codomain.
• C. tool in category theory chosen
  A tool in category theory is a conceptual or formal construct—such as functors, natural transformations, limits, or adjunctions—used to analyze, relate, and systematically reason about mathematical structures and their morphisms within the categorical framework.
• D. spectral sequence
  A spectral sequence is an algebraic tool in homological algebra and algebraic topology that computes complex (co)homology groups via a sequence of successive approximations organized in pages linked by differentials.
• E. 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.
• F. None of above.