differential geometry, the four-gradient (or 4-gradient) ∂ {\displaystyle {\boldsymbol {\partial }}} is the four-vector analogue of the gradient ∇ → {\displaystyle...

In vector calculus, the gradient of a scalar-valued differentiable function f {\displaystyle f} of several variables is the vector field (or vector-valued...

unit vectors, capital bold for four dimensional vectors (except for the four-gradient), and tensor index notation. A four-vector A is a vector with a "timelike"...

particle of matter with number n {\displaystyle n} . Physics portal Four-force Four-gradient Pauli–Lubanski pseudovector Taylor, Edwin; Wheeler, John (1992)...

}+\partial ^{\mu }f,} where ∂ μ {\displaystyle \partial ^{\mu }} is the four-gradient and f {\displaystyle f} is any harmonic scalar function: that is, a...

convention (+ − − −), are written in terms of the electromagnetic four-potential and the four-gradient as: F μ ν = ∂ μ A ν − ∂ ν A μ = [ 0 − E x / c − E y / c −...

denote the d'Alembertian; see below.) Quad, the 4-vector gradient operator or four-gradient, ( ∂ ∂ t , ∂ ∂ x , ∂ ∂ y , ∂ ∂ z ) {\displaystyle \textstyle...

electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two...

where ∂ / ∂ x α {\displaystyle \partial /\partial x^{\alpha }} is the four-gradient. This is the continuity equation. In general relativity, the continuity...

Perlin noise is a type of gradient noise developed by Ken Perlin in 1983. It has many uses, including but not limited to: procedurally generating terrain...

definition of the Lorentz factor. Physics portal Four-acceleration Four-momentum Four-force Four-gradient Algebra of physical space Congruence (general relativity)...

{r}{c}}\right)} where Θ {\displaystyle \Theta } is the Heaviside step function. Four-gradient d'Alembert's formula Klein–Gordon equation Relativistic heat conduction...

the gradient image is: Compare the edge strength of the current pixel with the edge strength of the pixel in the positive and negative gradient directions...

The histogram of oriented gradients (HOG) is a feature descriptor used in computer vision and image processing for the purpose of object detection. The...

is the four-velocity, and q {\displaystyle q} is the electric charge. four-vector four-velocity four-acceleration four-momentum four-gradient Grot, Richard...

relatively steep gradient, causing an increase in water velocity and turbulence. Flow, gradient, constriction, and obstacles are four factors that are...

Image Gradient Operator" at a talk at SAIL in 1968. Technically, it is a discrete differentiation operator, computing an approximation of the gradient of...

Christoffel symbols are no longer all zero. Four-vector Four-velocity Four-momentum Four-force Four-gradient Proper acceleration Tsamparlis M. (2010). Special...

{\displaystyle {\mathcal {L}}(\varphi ,\partial _{\mu }\varphi ,x_{\mu })} see four-gradient. The μ is an index which takes values 0 (for the time coordinate), and...

}A_{\mu }.} where ∂ {\displaystyle \partial } is the four-gradient and A {\displaystyle A} is the four-potential. SI units for Maxwell's equations and the...

E} is the total energy, and m 0 {\displaystyle m_{0}} is rest mass. Four-gradient: ∂ ν = ∂ ∂ x ν = ( 1 c ∂ ∂ t , − ∇ ) , {\displaystyle \partial ^{\nu...

The wave functions are denoted ψ, and ∂μ are the components of the four-gradient operator. In matrix equations, the Pauli matrices are denoted by σμ...

fields in manifest covariance; the partial derivatives that form the four-gradient ∂μ alone are not enough. The components which act on the color triplet...

c} is the speed of light. Setting the four-momentum P α {\displaystyle P_{\alpha }} equal to the four-gradient of the action S {\displaystyle S} , P α...

{\displaystyle \partial _{\gamma }T^{\beta \gamma }=0} where ∂γ is the four-gradient. (In non-Cartesian coordinates and general relativity this would be...

In numerical optimization, the nonlinear conjugate gradient method generalizes the conjugate gradient method to nonlinear optimization. For a quadratic...

proportional to the particle's concentration gradient. Fick's second law: Prediction of change in concentration gradient with time due to diffusion. A diffusion...

coordinates are shown below in the expression for the square of the four-gradient operator: We may rewrite the Kerr metric (1) in the following form:...

A pulsed field gradient is a short, timed pulse with spatial-dependent field intensity. Any gradient is identified by four characteristics: axis, strength...

common datum. The hydraulic head can be used to determine a hydraulic gradient between two or more points. In fluid dynamics, head is a concept that relates...