what does only right bracket in an equation such as b] = [A]y] means?

Question

I am writing a paper that uses one of the equations from an old(1969) paper

Now I have been asked the meaning of a single right bracket?

It seems it's differentiating between one dimensional and 2 dimensional matrices. However I cannot find anywhere any written description of what it means or is my interpretation correct? b] = [A]y]

Anyone from mathematical background provide a link to single side brackets and their interpretation?

Answer 1

The author appears to be using paired square brackets to indicate a matrix, and a single closing square bracket to indicate a column vector.

Let's perform the substitutions (and please pardon my crude rendering of mathematical notation, I don't know how to do it better):

log(β_i/α_i) = Σ_j=1ⁿ(g_ij-h_ij) log(X_j)

b_i = Σ_j=1ⁿ a_ij y_j

b_i = (A y)_i

b = A y

A is an mxn matrix, y is an nx1 column vector, and b is an mx1 column vector.