Involution : The Formal Theory of Differential Equations and its Applications in Computer Algebra Formal Geometry of Differential Equations Involution I: Algebraic Theory Completion to Involution Structure Analysis of Polynomial Modules Involution II: Homological Theory Involution III: Differential Theory The Size of the Formal Solution Space Existence and Uniqueness of Solutions Linear Differential Equations Miscellaneous Algebra Differential Geometry.