Diagonalization

In mathematics, diagonalization may refer to:

• Diagonal matrix, which is in a form with nonzero entries only on the main diagonal
• Diagonalizable matrix, which can be put into a form with nonzero entries only on the main diagonal
• Diagonal lemma, used to create self-referential sentences in formal logic
• Diagonal argument (disambiguation), various
• Cantor's diagonal argument, used to prove that the set of real numbers is not countable