I have just begun reading about Einstein's summation convention and it got me thinking..(adsbygoogle = window.adsbygoogle || []).push({});

Is it possible to represent ∑a_{i}b_{i}c_{i}with index notation? Since we are only restricted to use an index twice at most I don't think it's possible to construct it using the standard tensors (Levi Cevita and Kronecker Delta). Levi Cevita doesn't work because it's only non-zero when the indices are all different and Kronecker Delta only connects two tensors, leaving the third one behind. It becomes clearer if I think of them in terms of vectors and matrices.

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# I (Index Notation) Summing a product of 3 numbers

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