Number of Homomorphisms from D4 to Q8
To determine the number of homomorphisms from the dihedral group D4 to the quaternion group Q8, we need to analyze the structure of both groups and the properties of homomorphisms.
Diheral Group D4
The dihedral group D4 is the group of symmetries of a square. It has 8 elements and is generated by two elements: a rotation R of 90 degrees and a reflection F along a diagonal. The group multiplication table for D4 is as follows:
```
| e | R | R^2 | R^3 | F | FR | FR^2 | FR^3 |
----------------------------------------------------
e | e | R | R^2 | R^3 | F | FR | FR^2 | FR^3 |
----------------------------------------------------
R | R | R^2 | R^3 | e | FR | FR^2 | FR^3 | F |
----------------------------------------------------
R^2| R^2 | R^3 | e | R | FR^2 | FR^3 | F | FR |
----------------------------------------------------
R^3| R^3 | e | R | R^2 | FR^3 | F | FR | FR^2 |
----------------------------------------------------
F | F | FR | FR^2| FR^3| e | R | R^2 | R^3 |
----------------------------------------------------
FR | FR | FR^2| FR^3| F | R | R^2 | R^3 | e |
----------------------------------------------------
FR^2|FR^2| FR^3| F | FR | R^2 | R^3 | e | R |
----------------------------------------------------
FR^3|FR^3| F | FR | FR^2| R^3 | e | R | R^2 |
```
Quaternion Group Q8
The quaternion group Q8 is a non-abelian group of order 8. It can be represented by the following elements: {1, -1, i, -i, j, -j, k, -k}, where the multiplication table for Q8 is given by:
```
| 1 | -1 | i | -i | j | -j | k | -k |
--------------------------------------------------
1 | 1 | -1 | i | -i | j | -j | k | -k |
--------------------------------------------------
-1 | -1 | 1 | -i | i | -j | j | -k | k |
--------------------------------------------------
i | i | -i | -1 | 1 | k | -k | -j | j |
--------------------------------------------------
-i | -i | i | 1 | -1 | -k |