[r-t] Complexity of extents
matthew at frye.org.uk
Sat Jun 22 00:17:36 UTC 2013
On 21 Jun 2013, at 23:25, Mark Davies <mark at snowtiger.net> wrote:
> RAS writes,
>> The problem with that is that most general-purpose
>> compression programs (certainly including gzip) don't
>> understand a string occuring once forwards and a second
>> time backwards, e.g. "abcdefghijihgfedcba". Clearly that
>> string has structure, but gzip doesn't spot it.
> That's a good point. Perhaps it would be sensible to concatenate a reversed copy of the entire string, and compress the combined entity. This ought to produce a higher compression ratio for strings which have reversed elements within them.
But how many cases like this are you going to address? What about back-front symmetry? Rotational? Double? Dealing with them piecemeal isn't really very satisfactory (although the possible symmetries are finite, so we probably could deal with them all this way).
More information about the ringing-theory