Adjoint

In mathematics, the term adjoint applies in several situations. Several of these share a similar formalism: if A is adjoint to B, then there is typically some formula of the type

(Ax,y) = (x, By).

Specifically, adjoint may mean:

• Hermitian adjoint (adjoint of a linear operator) in functional analysis
• Adjoint functors in category theory
• Adjoint representation of a Lie group
• Adjoint endomorphism of a Lie algebra
• Conjugate transpose of a matrix in linear algebra
• Adjugate matrix, related to its inverse
• Adjoint equation
• The upper and lower adjoints of a Galois connection in order theory
• For the adjoint of a differential operator with general polynomial coefficients see differential operator