What is the Dual Nature of Nabla in Vector Differential Operators?

  • Context: Graduate 
  • Thread starter Thread starter abrowaqas
  • Start date Start date
  • Tags Tags
    Dual Nabla Nature
Click For Summary

Discussion Overview

The discussion revolves around the concept of the dual or hybrid nature of the nabla operator in vector differential calculus. Participants explore its role as a vector differential operator that can produce both vectors and scalars from different types of fields, including scalar and vector fields. The conversation touches on theoretical aspects and applications of nabla in various coordinate systems.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions the dual nature of nabla, asking if it means that nabla can produce a vector from a scalar field (gradient) and a scalar from a vector field (divergence).
  • Another participant explains that nabla behaves like an ordinary vector and can be used in dot and cross products with other vectors.
  • A different participant elaborates on the types of operations involving nabla, stating that multiplying a vector by a scalar yields a vector, while dot and cross products with vectors yield scalars and vectors, respectively.
  • One participant mentions their exam experience related to the hybrid nature of nabla and seeks clarification on a specific source discussing this concept.
  • Another participant references a book that describes nabla as both a vector and a derivative, noting that in non-Cartesian coordinates, the simple operations do not apply as they do in Cartesian coordinates.

Areas of Agreement / Disagreement

Participants express varying interpretations of nabla's dual nature, with some agreeing on its vector and derivative characteristics while others highlight the complexities in different coordinate systems. The discussion remains unresolved regarding a unified understanding of nabla's dual nature.

Contextual Notes

Participants note that the understanding of nabla's operations may depend on the coordinate system used, indicating potential limitations in applying the same principles universally.

abrowaqas
Messages
113
Reaction score
0
I didn't get the concept of dual or hybrid nature of nabla? I-e vector differential operator .. Is it means that nabla can produce a vector from scalar field (gradient) and scalar from vector field(divergence) ? What's the concept of Nabla's Dual nature ? Please explain..
 
Physics news on Phys.org
hi abrowaqas! :smile:

∇ behaves just like an ordinary vector …

the vector itself is ∇f (where f is a scalar)​

and you can dot-product it, or cross-product it, with a vector A …

∇.A (divA) or ∇xA (curlA) :wink:
 
If you multiply a vector by a scalar, you get a vector. If you multiply a vector by a vector (dot product) you get a scalar. If you multiply a vector by a vector (cross product), you get vector.

If that vector is "nabla" those three types of "multiplication" become
[tex]\nabla f(x,y,z)= grad f(x,y,z)[/tex]
[tex]\nabla\cdot\vec{f}(x,y,z)= div \vec{f}(x, y, z)[/tex]
[tex]\nabla\times\vec{f}(x,y,z)= curl \vec{f}(x, y, z)[/tex]
 
abrowaqas said:
what this link say about dual nature of nabla? can anybody explain?

http://books.google.com.pk/books?id...a=X&ei=p3g2T8DXJpSIhQe9jKn7AQ&ved=0CDwQ6AEwAg

oh, that's completely different from what i thought you were asking about! :rolleyes:

that book (by bernard maxum) is saying that ∇ is both a vector and a derivative …

in general (not cartesian) coordinates, the simple "dot" and "cross" procedure doesn't work …

that's what it means by the "dual nature" of ∇ :smile:
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 20 ·
Replies
20
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 13 ·
Replies
13
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K