octave: Evaluation Notation

 
 1.3.2 Evaluation Notation
 -------------------------
 
 In the examples in this manual, results from expressions that you
 evaluate are indicated with ‘⇒’.  For example:
 
      sqrt (2)
           ⇒ 1.4142
 
 You can read this as “‘sqrt (2)’ evaluates to 1.4142”.
 
    In some cases, matrix values that are returned by expressions are
 displayed like this
 
      [1, 2; 3, 4] == [1, 3; 2, 4]
           ⇒ [ 1, 0; 0, 1 ]
 
 and in other cases, they are displayed like this
 
      eye (3)
           ⇒  1  0  0
               0  1  0
               0  0  1
 
 in order to clearly show the structure of the result.
 
    Sometimes to help describe one expression, another expression is
 shown that produces identical results.  The exact equivalence of
 expressions is indicated with ‘≡’.  For example:
 
      rot90 ([1, 2; 3, 4], -1)
      ≡
      rot90 ([1, 2; 3, 4], 3)
      ≡
      rot90 ([1, 2; 3, 4], 7)