summation convention

summation convention

[sə′mā·shən kən‚ven·chən]
(mathematics)
An abbreviated notation used particularly in tensor analysis and relativity theory, in which a product of tensors is to be summed over all possible values of any index which appears twice in the expression.
References in periodicals archive ?
He shies away from the coordinate system and components of vectors and tensors whenever possible, and uses the Einstein summation convention extensively.