The Dictionary contains a discussion about transitive closure in the
entry for ^:
http://www.jsoftware.com/help/dictionary/d202n.htm
Example 5 starts as follows:
x=: (#x)<. (#x),~x=: (i.20)+1+20 [EMAIL PROTECTED] 3
(i.#x) ,: x
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
1 4 5 5 7 6 9 9 10 12 11 14 14 15 16 18 18 18 20 20 20
and includes the remark:
Interpretation: x specifies a directed graph with nodes numbered i.#x
and links from i to i{x . For example, the links are: 0 1 , 1 4 , 2 5
, 3 5 and so on. Then {&x^:a:0 or x{~^:a:0 computes all the nodes
reachable from node 0.
My question is about x being a directed graph.
Do all directed graphs consist of as many links as there are nodes?
Or is this example in some sense a special case?
Thanks
David
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
