Don't you mean an UNDIRECTED tree can be rooted at any of its nodes? For example, the following directed tree can not be rerooted:
0 1 0 2 Anyway, where is the verb "reroot" mentioned in your article from? Or were you speaking of a hypothetical "reroot"? ----- Original Message ----- From: Jose Mario Quintana <[EMAIL PROTECTED]> Date: Monday, May 19, 2008 9:13 Subject: Re: [Jprogramming] Displaying trees - J Wiki/Essays/Tree Sum To: Programming forum <[email protected]> > A directed tree can be rerooted at any of its nodes. For > example, t1 from > http://www.jsoftware.com/jwiki/Essays/Tree_Display , > > > |:t1 > 0 0 1 2 2 3 3 4 4 4 4 5 5 6 > 6 6 6 7 7 > 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 > tree t1 > +----------------------------+ > | ┌─ 14| > | ├─ 15| > | ┌─ 6 ─┼─ 16| > | │ └─ 17| > | ┌─ 1 ─── 3 ─┤ > ┌─ 18| > | > │ └─ > 7 ─┴─ 19| > | > │ ┌─ > 8 | > |─ 0 > ─┤ ├─ 9 | > | │ ┌─ 4 ─┼─ > 10 | > | │ > │ └─ 11 | > | └─ 2 ─┤ ┌─ > 12 | > | └─ > 5 ─┴─ 13 | > +----------------------------+ > > Can be rerooted at 3 as, > > tree t2=. 3 reroot t1 > +----------------------------------+ > | ┌─ > 14 | > | ├─ > 15 | > | ┌─ 6 ─┼─ > 16 | > | │ └─ > 17 | > | │ ┌─ > 18 | > | ├─ 7 ─┴─ > 19 | > |─ 3 > ─┤ ┌─ 8 | > | > │ ├─ 9 | > | > │ ┌─ 4 ─┼─ 10| > | > │ │ └─ 11| > | └─ 1 ─── 0 ─── 2 > ─┤ ┌─ 12| > | └─ 5 ─┴─ 13| > +----------------------------------+ > > |:t2 NB. (reroot rendering t2 or equivalent) > 3 3 6 6 6 6 7 7 3 1 0 2 2 4 > 4 4 4 5 5 > 6 7 14 15 16 17 18 19 1 0 2 4 5 8 9 10 11 12 13 > > > Has any J version of reroot been made public already? > > > ----- Original Message ---- > From: Roger Hui <[EMAIL PROTECTED]> > > Nothing new under the sun. > http://groups.google.com/group/comp.lang.apl/browse_thread/thread/5f1c1df7bd72fe51/32691205433c3152?lnk=gst#32691205433c3152 > > ----- Original Message ----- > From: Roger Hui <[EMAIL PROTECTED]> > > > http://www.jsoftware.com/jwiki/Essays/Tree_Display ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
