After more investigation, if after the commands
if get('itensor, 'version)=false then load (itensor) ;
idim(3);
dim:3;
defcon(q,q,qq);
expr:'levi_civita([i,k,m],[])*'levi_civita([],[i1,k,m])*q([],
[i])*q([i1],[])$
expr1:contract(expand(lc2kdt(expr)));
I enter
ishow(ev(expr1,kdelta));
the result is the expected " 2qq ", while if I enter
ishow(ev(contract(expand(lc2kdt(expr))),kdelta));
the result is " 5*qq-kdelta*qq ". Why the difference?
Thanks
On Jun 12, 2008, at 1:12 PM, Nicola Cabibbo wrote:
> Just trying to learn Maxima, with the commands:
>
> if get('itensor, 'version)=false then load (itensor) ;
> idim(3);
> dim:3;
> defcon(q,q,qq);
> expr:'levi_civita([i,k,m],[])*'levi_civita([],[i1,k,m])*q([],
> [i])*q([i1],[])$
> ishow(contract(expand(lc2kdt(expr))));
>
> I obtain " 5*qq-kdelta*qq ". This is correct with kdelta=3, but
> how can I directly obtain the simplified result "2 qq"?
>
> Thanks for the attention
>
> PS: my setup is (on a Mac)
>
> wxMaxima 0.7.5 http://wxmaxima.sourceforge.net
> Maxima 5.15.0 http://maxima.sourceforge.net
> Using Lisp CMU Common Lisp Snapshot 2008-03 (19E)
>
>
>
>
>
>