Bracket-Matching.md

-The Bracket Matching problem deals with parentheses `()`, square brackets `[]`, braces `{}` and other syntactic elements that provide for nested syntactic structures with balanced sets of delimiters.  
+The bracket matching problem deals with parentheses `()`, square brackets `[]`, braces `{}` and other syntactic elements that provide for nested syntactic structures with balanced sets of delimiters.  
 
+To tackle bracket matching with Parabix methods, a key concept is that of a 
+Nesting Depth BixNum.    This is a representation of the nesting depth of
+syntactic elements at each position in an input stream.    The following example
+shows an input stream with square brackets and braces, the corresponding nesting
+depth of each element in the data stream and the nesting depth bixnum (ND) as 
+a set of 3 parallel bit streams (giving a 3-bit number at each character position).
 ```
 Bracket Stream   ...[..{.}..{...[.[]..]..}...]...
 Nesting Depth    00011122211222233443332221111000