In order to align the above simple case with the more general convolution cases, we rename \boldsymbol{\alpha} , whose length is m=3 , with \boldsymbol{w} . We will interpret \boldsymbol{w} as a weight/filter function with which we want to perform the convolution with an input variable \boldsymbol{x} of length n . We will assume always that the filter \boldsymbol{w} has dimensionality m \le n .
We replace thus \boldsymbol{\beta} with \boldsymbol{x} and \boldsymbol{\delta} with \boldsymbol{y} and have
y(i)= \left(x*w\right)(i)= \sum_{k=0}^{k=m-1}w(k)x(i-k),where m=3 in our case, the maximum length of the vector \boldsymbol{w} . Here the symbol * represents the mathematical operation of convolution.