Clarify using matrices and tables

[wojtask]

Sometimes CLRS pseudocodes create empty matrices or tables (2D arrays):

• "let D be a new n\times n matrix" (page 772)
• "let m[1\subarr n, 1\subarr n] be a new table" (page 391)

Table elements are accessed using pairs of indices, e.g., m[i,j]. Matrix elements are accessed using lowercase letters with a pair of subscripts, e.g., d_{ij}.

We have a translation rule "let A[1\subarr n] be a new array" -> A = Array(1, n), and "A[i]" -> A[i].

Clarify how to translate the above examples. Explicitly add new translation rules for creation and accessors. Do we need a new Table type to encapsulate an Array of Arrays?

Moreover, sometimes arrays are also accessed with lowercase letters with a pair of subscripts, e.g., a_i. Do we need an explicit translation rule for it?