Difference between revisions of "Hook Length Theorem"

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[[File:Hook Example.png|200px|center]]
 
[[File:Hook Example.png|200px|center]]
  
Let the product of all the hooks in a tableau be h.Then, the Hook Length Theorem states that the number of SYTs is <cmath>\frac{n!}{k}</cmath>.
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Let the product of all the hooks in a tableau be h. Then, the Hook Length Theorem states that the number of SYTs is <math>\frac{n!}{h}</math>.

Revision as of 21:48, 5 November 2022

Introduction

The hook length theorem is a theorem to be used on Standard Young Tableau. A standard Young Tableau is essentially a pack of blocks together, such as this one:

Young Tableau.png

A tableau has a decreasing(not strictly decreasing) number of blocks in every row.

Tableau.png

A Standard Young Tableau(SYT) has increasing numbers in both rows and columns. As shown in the figure, 1-3-10 is increasing, as well as 2-5, 4-6, 7-9, 1-2-4-7-8, and 3-5-6-9.


Theorem

Let the number of blocks in the tableau be n. A hook of a block is the number of blocks to the right and below the block, including the block. In the below image, the hook of the red square is 7.

Hook Example.png

Let the product of all the hooks in a tableau be h. Then, the Hook Length Theorem states that the number of SYTs is $\frac{n!}{h}$.