# Technical Document Extraction: Issue sympy__sympy-21614
## 1. Document Header
* **Category:** Issue
* **Identifier:** sympy__sympy-21614
## 2. Issue Description
The document describes a bug report regarding the `kind` attribute in the SymPy library, specifically comparing the behavior of `Integral` versus `Derivative` when applied to a `MatrixSymbol`.
### Text Transcription:
"We're currently solving the following issue within our repository. Here's the issue text:
ISSUE:
Wrong Derivative kind attribute
I'm playing around with the 'kind' attribute.
The following is correct:"
### Code Block 1: Correct Behavior (Integral)
```python
from sympy import Integral, Derivative
from sympy import MatrixSymbol
from sympy.abc import x
A = MatrixSymbol('A', 2, 2)
i = Integral(A, x)
i.kind
# MatrixKind(NumberKind)
```
* **Observation:** When an `Integral` is performed on a 2x2 `MatrixSymbol`, the `.kind` attribute correctly returns `MatrixKind(NumberKind)`.
### Text Transcription (Continued):
"This one is wrong:"
### Code Block 2: Incorrect Behavior (Derivative)
```python
d = Derivative(A, x)
d.kind
# UndefinedKind
```
* **Observation:** When a `Derivative` is performed on the same `MatrixSymbol`, the `.kind` attribute returns `UndefinedKind`, which is identified as the bug.
## 3. Environment and Instructions
* **INSTRUCTIONS:** (31 lines)
* **Open file:** n/a
* **Current directory:** `/sympy__sympy`
* **Terminal Prompt:** `bash-$`
## 4. Summary of Technical Data
| Component | Input Object | Operation | Expected/Observed Kind | Status |
| :--- | :--- | :--- | :--- | :--- |
| Integral | MatrixSymbol('A', 2, 2) | `Integral(A, x)` | `MatrixKind(NumberKind)` | Correct |
| Derivative | MatrixSymbol('A', 2, 2) | `Derivative(A, x)` | `UndefinedKind` | **Incorrect** |
**Technical Conclusion:** The `Derivative` class in SymPy fails to properly propagate or assign the `kind` attribute when operating on matrix types, whereas the `Integral` class handles it correctly.
