I have a complex valued function $f:[0,1]\longrightarrow \mathbb{C}$ and I want to minimise a functional of the form: $ J = \int_{0}^{1} g(|f(x)|^2) \,dx $ where $g$ is some function. So the functional $J$ is real, even though $f$ is complex. Can I apply the Euler Lagrange equations and get an ODE in terms of $f$ or $f^*$, or is this unjustified because $f$ is complex valued?
2026-03-29 11:18:35.1774783115
Can you apply the Euler-Lagrange equations when trying to find the extrema of a (real valued) functional of a complex function?
85 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail AtRelated Questions in COMPLEX-ANALYSIS
- Minkowski functional of balanced domain with smooth boundary
- limit points at infinity
- conformal mapping and rational function
- orientation of circle in complex plane
- If $u+v = \frac{2 \sin 2x}{e^{2y}+e^{-2y}-2 \cos 2x}$ then find corresponding analytical function $f(z)=u+iv$
- Is there a trigonometric identity that implies the Riemann Hypothesis?
- order of zero of modular form from it's expansion at infinity
- How to get to $\frac{1}{2\pi i} \oint_C \frac{f'(z)}{f(z)} \, dz =n_0-n_p$ from Cauchy's residue theorem?
- If $g(z)$ is analytic function, and $g(z)=O(|z|)$ and g(z) is never zero then show that g(z) is constant.
- Radius of convergence of Taylor series of a function of real variable
Related Questions in CALCULUS-OF-VARIATIONS
- On sufficient condition for pre-compactness "in measure"(i.e. in Young measure space)
- Weak formulation of Robin boundary condition problem
- Why is the index of a harmonic map finite?
- Variational Formulation - inhomogeneous Neumann boundary
- Relationship between Training Neural Networks and Calculus of Variations
- How to prove a Minimal Surface minimizes Surface Tension
- Derive the Euler–Lagrange equation for a functional a single variable with higher derivatives.
- Does the covariant derivative commute with the variational derivative?
- Derivative of a functional w.r.t. a single point?
- calculus of variations with double integral textbook?
Related Questions in EULER-LAGRANGE-EQUATION
- Showing solution to this function by Euler-Lagrange
- Derive the Euler–Lagrange equation for a functional a single variable with higher derivatives.
- Functional with 4th grade characteristic equation
- derivative of double integral in calculus of variation
- When is the Euler-Lagrange equation trivially satisfied?
- Euler-Lagrange and total derivative of partial derivative for function of two variables
- Energy Functional from the Euler-Lagrange Equations
- Find differential equation using variation principle and lagrangian
- Euler-Lagrange equations without lower boundary conditions
- Finding First Variation
Trending Questions
- Induction on the number of equations
- How to convince a math teacher of this simple and obvious fact?
- Find $E[XY|Y+Z=1 ]$
- Refuting the Anti-Cantor Cranks
- What are imaginary numbers?
- Determine the adjoint of $\tilde Q(x)$ for $\tilde Q(x)u:=(Qu)(x)$ where $Q:U→L^2(Ω,ℝ^d$ is a Hilbert-Schmidt operator and $U$ is a Hilbert space
- Why does this innovative method of subtraction from a third grader always work?
- How do we know that the number $1$ is not equal to the number $-1$?
- What are the Implications of having VΩ as a model for a theory?
- Defining a Galois Field based on primitive element versus polynomial?
- Can't find the relationship between two columns of numbers. Please Help
- Is computer science a branch of mathematics?
- Is there a bijection of $\mathbb{R}^n$ with itself such that the forward map is connected but the inverse is not?
- Identification of a quadrilateral as a trapezoid, rectangle, or square
- Generator of inertia group in function field extension
Popular # Hahtags
second-order-logic
numerical-methods
puzzle
logic
probability
number-theory
winding-number
real-analysis
integration
calculus
complex-analysis
sequences-and-series
proof-writing
set-theory
functions
homotopy-theory
elementary-number-theory
ordinary-differential-equations
circles
derivatives
game-theory
definite-integrals
elementary-set-theory
limits
multivariable-calculus
geometry
algebraic-number-theory
proof-verification
partial-derivative
algebra-precalculus
Popular Questions
- What is the integral of 1/x?
- How many squares actually ARE in this picture? Is this a trick question with no right answer?
- Is a matrix multiplied with its transpose something special?
- What is the difference between independent and mutually exclusive events?
- Visually stunning math concepts which are easy to explain
- taylor series of $\ln(1+x)$?
- How to tell if a set of vectors spans a space?
- Calculus question taking derivative to find horizontal tangent line
- How to determine if a function is one-to-one?
- Determine if vectors are linearly independent
- What does it mean to have a determinant equal to zero?
- Is this Batman equation for real?
- How to find perpendicular vector to another vector?
- How to find mean and median from histogram
- How many sides does a circle have?