Wedgie/Archived version: Difference between revisions
Wikispaces>genewardsmith **Imported revision 141665907 - Original comment: ** |
Wikispaces>genewardsmith **Imported revision 141666273 - Original comment: ** |
||
| Line 1: | Line 1: | ||
<h2>IMPORTED REVISION FROM WIKISPACES</h2> | <h2>IMPORTED REVISION FROM WIKISPACES</h2> | ||
This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br> | This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br> | ||
: This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2010-05-13 03: | : This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2010-05-13 03:44:07 UTC</tt>.<br> | ||
: The original revision id was <tt> | : The original revision id was <tt>141666273</tt>.<br> | ||
: The revision comment was: <tt></tt><br> | : The revision comment was: <tt></tt><br> | ||
The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.<br> | The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.<br> | ||
| Line 16: | Line 16: | ||
f^g = sum_s sgn(s) f(x_s(1), x_s(2)...x_s_n)g(x_s(n+1)...x_s(n+m)) | f^g = sum_s sgn(s) f(x_s(1), x_s(2)...x_s_n)g(x_s(n+1)...x_s(n+m)) | ||
where the sum is taken over S(n,m), the set of all [[http://en.wikipedia.org/wiki/Permutation|permutations]] of the first n+m integers which are an [[http://en.wikipedia.org/wiki/%28p,q%29_shuffle|(n,m) shuffles]], and sgn(t) is the [[http://en.wikipedia.org/wiki/Parity_of_a_permutation|parity of the permutation]] t, which is +1 is even meaning an even number of transpositions of two numbers will get to t, and -1 if | where the sum is taken over S(n,m), the set of all [[http://en.wikipedia.org/wiki/Permutation|permutations]] of the first n+m integers which are an [[http://en.wikipedia.org/wiki/%28p,q%29_shuffle|(n,m) shuffles]], and sgn(t) is the [[http://en.wikipedia.org/wiki/Parity_of_a_permutation|parity of the permutation]] t, which is +1 if t is even meaning an even number of transpositions of two numbers will get to t, and -1 if t is odd. | ||
If f and g are both vals (1-maps) then this becomes especially easy: f^g(u,v) = f(u)g(v) - f(v)g(u). | If f and g are both vals (1-maps) then this becomes especially easy: f^g(u,v) = f(u)g(v) - f(v)g(u). | ||
| Line 32: | Line 32: | ||
f^g = sum_s sgn(s) f(x_s(1), x_s(2)...x_s_n)g(x_s(n+1)...x_s(n+m))<br /> | f^g = sum_s sgn(s) f(x_s(1), x_s(2)...x_s_n)g(x_s(n+1)...x_s(n+m))<br /> | ||
<br /> | <br /> | ||
where the sum is taken over S(n,m), the set of all <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Permutation" rel="nofollow">permutations</a> of the first n+m integers which are an <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/%28p,q%29_shuffle" rel="nofollow">(n,m) shuffles</a>, and sgn(t) is the <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Parity_of_a_permutation" rel="nofollow">parity of the permutation</a> t, which is +1 is even meaning an even number of transpositions of two numbers will get to t, and -1 if | where the sum is taken over S(n,m), the set of all <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Permutation" rel="nofollow">permutations</a> of the first n+m integers which are an <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/%28p,q%29_shuffle" rel="nofollow">(n,m) shuffles</a>, and sgn(t) is the <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Parity_of_a_permutation" rel="nofollow">parity of the permutation</a> t, which is +1 if t is even meaning an even number of transpositions of two numbers will get to t, and -1 if t is odd.<br /> | ||
<br /> | <br /> | ||
If f and g are both vals (1-maps) then this becomes especially easy: f^g(u,v) = f(u)g(v) - f(v)g(u).</body></html></pre></div> | If f and g are both vals (1-maps) then this becomes especially easy: f^g(u,v) = f(u)g(v) - f(v)g(u).</body></html></pre></div> | ||