Solving some functional and operational equations.
Some complex matrix and determinant functional equations.
Some propositions related to a dilation theorem of W. Benz.
Submultiplicative functions and operator inequalities
Let T: C¹(ℝ) → C(ℝ) be an operator satisfying the “chain rule inequality” T(f∘g) ≤ (Tf)∘g⋅Tg, f,g ∈ C¹(ℝ). Imposing a weak continuity and a non-degeneracy condition on T, we determine the form of all maps T satisfying this inequality together with T(-Id)(0) < 0. They have the form Tf = ⎧ , f’ ≥ 0, ⎨ ⎩ , f’ < 0, with p > 0, H ∈ C(ℝ), A ≥ 1. For A = 1, these are just the solutions of the chain rule operator equation. To prove this, we characterize the submultiplicative, measurable functions...
Sur les opérations en général et les équations différentielles linéaires d'ordre infini
Sur les transmutations