[hackers] [libzahl] zptest.3: why it is called NONPRIME rather than COMPOSITE || Mattias Andrée

[git]

commit e702b9682fcd87fac3ce169e2c98d0c409a6f7e0
Author:     Mattias Andrée <maand...@kth.se>
AuthorDate: Sun May 1 01:20:52 2016 +0200
Commit:     Mattias Andrée <maand...@kth.se>
CommitDate: Sun May 1 01:20:52 2016 +0200

    zptest.3: why it is called NONPRIME rather than COMPOSITE
    
    Signed-off-by: Mattias Andrée <maand...@kth.se>

diff --git a/man/zptest.3 b/man/zptest.3
index f8193d0..dd35430 100644
--- a/man/zptest.3
+++ b/man/zptest.3
@@ -45,7 +45,7 @@ This function will either return:
 .TP
 .B NONPRIME
 .I questioned
-is certainly a composite number.
+is certainly a nonprime number (composite).
 .TP
 .B PROBABLY_PRIME
 .I questioned
@@ -70,5 +70,11 @@ the chance that
 .B PRIME
 is returned.
 .IR witness .
+.SH RATIONALE
+.B NONPRIME
+is called just that, rather than COMPOSITE,
+because negative integers, zero, and one are
+neither prime nor composite. (One was historically
+a prime, we do not recognise it as such.)
 .SH SEE ALSO
 .BR zgcd (3)