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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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* Tensor index contraction
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if get('itensor,'version)=false then load(itensor);
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("defcon() assigns contraction properties to tensors")$
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ishow(e([a],[b])*f([b],[c]))$
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("kdelta is the Kronecker delta with special contraction properties")$
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ishow(contract(kdelta([a],[b])*kdelta([b],[a])))$
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("The imetric() function sets up contraction properties for the metric")$
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ishow(contract(rename(expand(%))))$
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("The contract() function can also raise and lower indices")$
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ishow(Te([i,j],[k,l])*Ti([k,m])*Ti([l,n]))$
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ishow(Te([i,j],[k,l])*Ti([],[i,n])*Ti([],[j,m]))$
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/* End of demo -- comment line needed by MAXIMA to resume demo menu */