# Questions tagged [operators]

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

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1answer
70 views

### Can I control depths in Inner?

I want to optimize the code like this: ...
0answers
67 views

### Superposition of the differential operators

My problem can be easily solved without Mathematica, however, I am curious how to do it in Mathematica. Moreover, I can be stuck with a similar, but more cumbersome problems in the future. Following ...
1answer
156 views

### Raising, lowering and number operators for Dirac notation

Starting from this very interesting post Defining quantum-mechanical Bra and Ket operations, i would like to implement raising, lowering and number operators, taking into account that they might be ...
0answers
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1answer
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### Single argument operator form?

I've heard the explanation that functions like StringDrop[] are varargs and so that is why they do not have an operator form. But when you are only using the ...
1answer
65 views

### odd matrix operation [closed]

This is for the case of a 10 x 10 matrix. I have the matrix ...
2answers
156 views

0answers
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### Defining a complex partial differential operator

I tried to define a partial differential operator using this code ...
2answers
115 views

### Custom opaque operator with custom axioms?

Is there any way to define a custom opaque operator/function in Mathematica that satisfies custom axioms, so that the Mathematica engine can perform simplifications using those axioms? For example, ...
0answers
69 views

### How can I realize operator $\frac{D}{e^D-1}$ in Mathematica?

Especially if it is applied to an integral of a function. So, I need for a given function f[t] the following: $\frac{D}{e^D-1} \int_0^t f(t)dt |_{t=\omega}$
1answer
651 views

1answer
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### Difference between = and := [duplicate]

I wanted to know the difference between two operators: = and := I couldn't find the ":=" operator on the list at https://reference.wolfram.com/language/tutorial/Operators.html Can someone help? ...
4answers
221 views

### How to implement the action of a shift operator on arbitrary functions?

How can I expand expressions like $$(1-g(x)D)\frac{1}{1-f(x)D},$$ where $f(x),g(x)$ are some functions and $D$ is the shift operator defined by $Dh(x)=h(x+a)D$. What I'm trying to do is to formally ...
1answer
573 views

### What does “slash at” mean /@? [closed]

I searched "slash at" as well as "/@" to no avail. Consider Normalize /@ A I see the net effect, but what does /@ really mean? I understand that @ can be used ...
0answers
50 views

### Operator Splitting and Taylore series

I am not a user of mathematica so I am not sure if what I want to do is possible. Imagine I have the following cauchy problem: $$\frac{dw}{dt} = F(t, w(t)) = f1(w(t), t) + f2(w(t), t)$$ where I have ...
1answer
99 views

### Generating a list of values from the application of a sequence of operators

I have a module 'L' that reads: L[f0_,n_]:=Module[{ft=f0}, a[t]={}; Do[AppendTo[a[t], Inr[f0,ft]]; ft=U@ft, {n}]]; It takes an input function f0, applies ...
2answers
176 views

### Product of n different operators

I have a sequence of differential operators given by $H_n = x \frac{d}{dx} + n$ where $n=1,2,...$ and I would like to construct the operator $\hat{O}(n) = \frac{1}{n!}H_nH_{n-1}...H_2H_1$ as a ...
1answer
1k views

### I want to be able to define (a(x) d/dx + b(x))^n

I want to be able to define an operator $(a(x) d/dx + b(x))^n$ where $d/dx$ is the derivative operator and $a(x)$ and $b(x)$ are known functions and $n$ is a positive integer. Related Query: How ...
0answers
310 views

### Non commutative products and scalars

Say I have an expression such as $$a.(\alpha b)$$ where $a$ and $b$ are non-commutative operators, but $\alpha$ is simply a scalar. How do I tell Mathematica to treat $\alpha$ as a scalar and "pull" ...
1answer
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1answer
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### Differential equations expressed in operator form [duplicate]

Is it possible to make a workable operator representation of differential equations in Mathematica? I think it would make solving my differential equations easier, but I have no idea how to do it. ...