MyWikiBiz, Author Your Legacy — Saturday December 28, 2024
Jump to navigationJump to search
407 bytes added
, 13:45, 15 June 2009
Line 3,761: |
Line 3,761: |
| |} | | |} |
| | | |
− | <pre>
| + | From the relational representation of <math>\operatorname{Sym} \{ a, b, c \} \cong S_3,</math> one easily derives a ''linear representation'' of the group by viewing each permutation as a linear transformation that maps the elements of a suitable vector space into each other. Each of these linear transformations is in turn represented by the a 2-dimensional array of coefficients in <math>\mathbb{B},</math> resulting in the following set of matrices for the group: |
− | From this relational representation of Sym {a, b, c} ~=~ S_3, | |
− | one easily derives a "linear representation", regarding each | |
− | permutation as a linear transformation that maps the elements | |
− | of a suitable vector space into each other, and representing | |
− | each of these linear transformations by means of a matrix,
| |
− | resulting in the following set of matrices for the group: | |
| | | |
− | Table 21. Matrix Representations of the Permutations in S_3
| + | <br> |
− | o---------o---------o---------o---------o---------o---------o
| |
− | | | | | | | |
| |
− | | e | f | g | h | i | j |
| |
− | | | | | | | |
| |
− | o=========o=========o=========o=========o=========o=========o
| |
− | | | | | | | |
| |
− | | 1 0 0 | 0 0 1 | 0 1 0 | 1 0 0 | 0 0 1 | 0 1 0 |
| |
− | | 0 1 0 | 1 0 0 | 0 0 1 | 0 0 1 | 0 1 0 | 1 0 0 |
| |
− | | 0 0 1 | 0 1 0 | 1 0 0 | 0 1 0 | 1 0 0 | 0 0 1 |
| |
− | | | | | | | |
| |
− | o---------o---------o---------o---------o---------o---------o
| |
| | | |
− | The key to the mysteries of these matrices is revealed by
| + | {| align="center" border="1" cellpadding="8" cellspacing="0" style="background:#f8f8ff; text-align:center; width:90%" |
− | observing that their coefficient entries are arrayed and
| + | |+ <math>\text{Matrix Representations of Permutations in}~ \operatorname{Sym}(3)</math> |
− | overlayed on a place mat that's marked like so:
| + | |- style="background:#f0f0ff" |
| + | | width="16%" | <math>\operatorname{e}</math> |
| + | | width="16%" | <math>\operatorname{f}</math> |
| + | | width="16%" | <math>\operatorname{g}</math> |
| + | | width="16%" | <math>\operatorname{h}</math> |
| + | | width="16%" | <math>\operatorname{i}</math> |
| + | | width="16%" | <math>\operatorname{j}</math> |
| + | |- |
| + | | |
| + | <math>\begin{matrix} |
| + | 1 & 0 & 0 |
| + | \\ |
| + | 0 & 1 & 0 |
| + | \\ |
| + | 0 & 0 & 1 |
| + | \end{matrix}</math> |
| + | | |
| + | <math>\begin{matrix} |
| + | 0 & 0 & 1 |
| + | \\ |
| + | 1 & 0 & 0 |
| + | \\ |
| + | 0 & 1 & 0 |
| + | \end{matrix}</math> |
| + | | |
| + | <math>\begin{matrix} |
| + | 0 & 1 & 0 |
| + | \\ |
| + | 0 & 0 & 1 |
| + | \\ |
| + | 1 & 0 & 0 |
| + | \end{matrix}</math> |
| + | | |
| + | <math>\begin{matrix} |
| + | 1 & 0 & 0 |
| + | \\ |
| + | 0 & 0 & 1 |
| + | \\ |
| + | 0 & 1 & 0 |
| + | \end{matrix}</math> |
| + | | |
| + | <math>\begin{matrix} |
| + | 0 & 0 & 1 |
| + | \\ |
| + | 0 & 1 & 0 |
| + | \\ |
| + | 1 & 0 & 0 |
| + | \end{matrix}</math> |
| + | | |
| + | <math>\begin{matrix} |
| + | 0 & 1 & 0 |
| + | \\ |
| + | 1 & 0 & 0 |
| + | \\ |
| + | 0 & 0 & 1 |
| + | \end{matrix}</math> |
| + | |} |
| | | |
− | o-----o-----o-----o
| + | <br> |
− | | a:a | a:b | a:c | | + | |
− | o-----o-----o-----o
| + | The key to the mysteries of these matrices is revealed by observing that their coefficient entries are arrayed and overlaid on a place-mat marked like so: |
− | | b:a | b:b | b:c |
| + | |
− | o-----o-----o-----o
| + | {| align="center" cellpadding="6" width="90%" |
− | | c:a | c:b | c:c |
| + | | align="center" | |
− | o-----o-----o-----o
| + | <math>\begin{bmatrix} |
− | </pre> | + | a\!:\!a & |
| + | a\!:\!b & |
| + | a\!:\!c |
| + | \\ |
| + | b\!:\!a & |
| + | b\!:\!b & |
| + | b\!:\!c |
| + | \\ |
| + | c\!:\!a & |
| + | c\!:\!b & |
| + | c\!:\!c |
| + | \end{bmatrix}</math> |
| + | |} |
| | | |
| ==Note 22== | | ==Note 22== |