The Matrix Cookbook

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04 - Complex Matrices

Advanced formula selection, assumption checking, and exact application for Complex Matrices, book pages 24-27.

Learning path

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0 of 2 sections marked complete · about 25 minutes

Learning objectives

What you will be able to explain

  • Complex matrix operators
  • Complex derivative discipline
  • Complex quadratic gradient
  • Higher-order and nonlinear derivatives
  • Inverse of a complex sum
  • Hermitian checks

Section 01

Complex matrix operators to Complex quadratic gradient

01

Complex matrix operators

Hermitian transpose combines conjugation and transposition.

Guided checkpoint

Match notation to meaning.

Source: Notation, p. 5; Sec. 4, pp. 24-27

02

Complex derivative discipline

Wirtinger-style calculus separates variable and conjugate-variable dependence.

Guided checkpoint

For a non-analytic real-valued function of complex variables, judge the approach.

Source: Sec. 4.1, pp. 24-26

03

Complex quadratic gradient

The Hermitian form generalizes the real quadratic form and is real for Hermitian AA.

Guided checkpoint

For Hermitian AA, which expression is the natural quadratic scalar?

Source: Sec. 4.1, pp. 24-26

Section 02

Higher-order and nonlinear derivatives to Hermitian checks

01

Higher-order and nonlinear derivatives

Nonlinearity and conjugate dependence invalidate naive scalar analogies.

Guided checkpoint

Audit conceptual requirements.

Source: Sec. 4.2, pp. 26-27

02

Inverse of a complex sum

The provided identities account for coupling; (A+B)1(A+B)^{-1} does not distribute.

Guided checkpoint

What is the safe general strategy for an inverse containing real and imaginary matrix parts?

Source: Sec. 4.3, p. 27

03

Hermitian checks

Hermitian is conjugate symmetry, not necessarily ordinary symmetry.

Guided checkpoint

Let H=HHH=H^H.

Source: Sec. 4 and Sec. 9.3, pp. 24-27,48

Knowledge check

Turn understanding into recall.

The quiz now follows the same concepts in scored form. You can return to this lesson from the quiz whenever a gap appears.