# Questions tagged [operators]

Questions about using or composing operators--functional mappings from one state or vector space to another.

183 questions
Filter by
Sorted by
Tagged with
30 views

### Implicit definition of a coordinate in differential equation [duplicate]

I would like to solve the following differential equation $\frac{d^2 \psi(r_*)}{dr^2_*} + (\omega^2 - V(r)) \psi(r_*)=0$ and the boundary conditions are $\psi(\inf) = \psi(-inf) = 0$. The problem is ...
34 views

45 views

### Problem with defining a simple linear operator

I need to define a linear operator, which should have very simple linearity: myOp[Plus[f_, g_]] := myOp[f] + myOp[g] myOp[a_ f_[x_, t_]] := a myOp[f[x, t]] where ...
70 views

### Simplify differential expressions

One can differentiate a two dimensional vector like this, ClearAll["Global`*"] u[x_, y_] := {f[x, y], g[x, y]} Div[u[x, y], {x, y}] with output ...
130 views

### How can I define operators that implement the algebra of sets?

I need to define some operators with properties like idempotence and distribution over union and intersection so that Mathematica can symbolically simplify expressions. How do I define such operators? ...
37 views

### Define different actions for the same operator depending on the nature of its arguments

I am working with terms of the form A**B1**B2 where A, B1, and ...
96 views

### Defining an operator with given properties

In symbolic derivations with Mathematica, one often needs to define an operator with some desired properties, which will be used to stand for a general function or transform. For example, I would ...
165 views

### Defining a complex partial differential operator

I tried to define a partial differential operator using this code ...
39 views

77 views

### Lowering operator for spherical harmonics [duplicate]

I need to be able to generate all of the $l=2$ spherical harmonics using the lowering operator. The specific question is listed below. Any assistance would be much appreciated! Thanksenter image ...
135 views

### Partial trace and Partial Transposition of a matrix easily? [closed]

Could someone help me to understand as to how to compute the partial trace and partial-transposition of an arbitrary matrix? I mean, is there any code to carry out these operations in Mathematica? ...
112 views

40 views

### How do you treat gradient as a vector? [duplicate]

I need to express $\nabla = (\partial_x,\partial_y,\partial_z)$ as a vector, so that I can compute the differential operator given by $A\cdot\nabla$ (where here $A$ is a 3x3 matrix) using Mathematica. ...
I would like to define a derivation in Mathematica. As an example something like this: for an operator O and operators $A,B$ in a two dimensional vector space with  O \times A = a \\ O \times B = b \...
What would be the best way to define the Moyal Product, $f(x,p)\star g(x,p)$, in Mathematica? $f(x,p)\star g(x,p)$ may be written as \$f\star g=\sum\limits_{n=0}^{\infty}\frac{1}{n!}\left(\frac{i\hbar}...