# Matrix consisting of the matrices [duplicate]

I need Dirac Matrix in my work. They consists of PauliMatrix and ZeroMatrix, which is:

ZeroMatrix:=IdentityMatrix[2]-IdentityMatrix[2]


I define Dirac Matrix as:

gamma = ({{PauliMatrix[0], ZeroMatrix}, {ZeroMatrix, -PauliMatrix[0]}}) // MatrixForm;


I got such result:

But I need something else: I need a monolithic table, does not consist of individual blocks. How can I get it? (I need something universal, because I need to use it to construct 4 gamma matrices and spinors).

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## marked as duplicate by Artes, Mr.Wizard♦Aug 13 '14 at 21:28

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

In fact this is a special case of How to Flatten Array of Arrays of the highest order in a simple way? – Artes Aug 13 '14 at 18:58
Array[0 &, {2, 2}] would be better than IdentityMatrix - IdentityMatrix :) – Öskå Aug 13 '14 at 19:00
@Artes Why not vote to close? Also a duplicate of (761) I believe. – Mr.Wizard Aug 13 '14 at 21:05
@Mr.Wizard I've done it, but since I've been one of the most frequent reviewers I expected others to start closing. – Artes Aug 13 '14 at 21:26
@Artes There is no obligation but as it takes no longer to vote to close than it does to comment why not vote? – Mr.Wizard Aug 13 '14 at 21:27

## 1 Answer

ArrayFlatten[] takes zeroes as a representation of a zero square matrix:

gamma = {{PauliMatrix[0], 0}, {0, -PauliMatrix[0]}}
ArrayFlatten[gamma]


Which gives {{1, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, -1, 0}, {0, 0, 0, -1}}

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