Question

An index which is repeated in a given expression so that the summation
convection applies, is called​

Answer 1

Answer:

Summation convention

is the answer

Answer 2

Answer:

A letter of the repeated suffix is arbitrary and thus it is called the dummy index as known from.

Step-by-step explanation:

(1.1) A letter of the repeated suffix is arbitrary and thus it is called the dummy index as known from.

(1.2)This rule is also called Einstein's summation convention. A repeated index obeys this convention unless otherwise specified by the additional remark “(no sum)” after an equation.