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## Homework Statement

Not a specific problem; I'm trying to understand what the notation means; I'm using primarily Griffiths, Marion and Jackson textbooks.

The notation for a matrix, with the superscript row index and subscript column index I understand. For the EM field tensor, Griffiths has both indices superscripted, and Marion has both subscripted. My questions are:

1. What is the difference?

2. What is the meaning when they are both on the same level? I assume one is rows and one is columns - but which is which?

3. When you take a derivative of the tensor, what exactly are you doing in terms of the indices of the tensor and the index of the variable of integration?