These are **things named after Jacques Hadamard** (1865–1963), a French mathematician. (For references, see the respective articles.)

- Cartan–Hadamard theorem
- Cauchy–Hadamard theorem
- Hadamard product:
- entry-wise matrix multiplication
- an infinite product expansion for the Riemann zeta function

- Hadamard code
- Hadamard's dynamical system
- Hadamard's inequality
- Hadamard's method of descent
- Hadamard finite part integral
- Hadamard's lemma
- Hadamard manifold
- Hadamard matrix
- Hadamard's maximal determinant problem
- Hadamard space
- Hadamard three-circle theorem
- Hadamard Transform and Hadamard gate
- Hadamard–Rybczynski equation
- Ostrowski–Hadamard gap theorem

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