How to Write the Inverse of a Matrix Using Einstein Summation Notation?

In summary, the dot product in terms of summation notation is represented as ##\textbf{a.b} = a^{\alpha}b_{\alpha}##. The Levi-Cevita symbol is used in the cross product. The inverse of Aij is written as AijAij=σ ij, with the indices moving downstairs.
  • #1
Mathematicsresear
66
0

Homework Statement


I am unsure as to how to write the dot product in terms of the summation notation? May you please explain?

Homework Equations

The Attempt at a Solution

 
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  • #2
Do you mean ##\textbf{a.b} = a^{\alpha}b_{\alpha}##?
 
  • #4
PeroK said:
Do you mean ##\textbf{a.b} = a^{\alpha}b_{\alpha}##?
Yes, why is one index is on the top? and the other on the bottom? What about the Levi cevita symbol?
 
  • #5
Mathematicsresear said:
Yes, why is one index is on the top? and the other on the bottom? What about the Levi cevita symbol?

In addition to the link given in post #3, there must be lots online about the summation convention. Where are you learning this?

The subscript (lower index) indicates the components of a "dual vector" or "covector".

Levi-Civita is used in the cross product.
 
  • #6
how would you write the inverse of Aij is it simply moving the indices downstairs AijAijij (where do the indices go, up down or split?)
 

Related to How to Write the Inverse of a Matrix Using Einstein Summation Notation?

1. What is Einstein Summation Notation?

Einstein Summation Notation is a mathematical notation used to represent and simplify complicated mathematical expressions involving summation. It is named after the famous physicist Albert Einstein, who used this notation extensively in his work on the theory of relativity.

2. How is Einstein Summation Notation written?

Einstein Summation Notation uses a combination of Greek and Latin letters to represent the indices of summation and the variables being summed. The notation is written as a capital sigma symbol (∑) with the indices and variables written below and above it respectively, with a subscript indicating the range of the summation.

3. What is the purpose of using Einstein Summation Notation?

The purpose of using Einstein Summation Notation is to simplify and condense complicated mathematical expressions involving summation. It allows for a more compact and concise representation of these expressions, making them easier to understand and work with.

4. How is Einstein Summation Notation used in physics?

In physics, Einstein Summation Notation is commonly used in tensor analysis, which is a mathematical tool used to describe the properties of physical systems. It is also used in the theory of relativity, electromagnetism, and quantum mechanics to represent and solve complex equations.

5. Are there any rules or conventions for using Einstein Summation Notation?

Yes, there are some rules and conventions that should be followed when using Einstein Summation Notation. These include keeping the indices in the same order on both sides of the expression, using the same index for repeated variables, and avoiding ambiguous expressions by using different indices for different variables.

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