Add \Nn macro for cartesian products of the natural numbers.

diff --git a/mjo-common.tex b/mjo-common.tex
index 40a7d6c243f657f2f2d1809709bacded8499d74d..a4457883acbea4f39adfa6e90e63684533e37eed 100644 (file)
--- a/mjo-common.tex
+++ b/mjo-common.tex
@@ -32,6 +32,11 @@
 % will be omitted entirely.
 %
 
+% The natural n-space, N x N x N x ... x N.
+\providecommand*{\Nn}[1][n]{
+  \mathbb{N}\if\detokenize{#1}\detokenize{1}{}\else^{#1}\fi
+}
+
 % The integral n-space, Z x Z x Z x ... x Z.
 \providecommand*{\Zn}[1][n]{
   \mathbb{Z}\if\detokenize{#1}\detokenize{1}{}\else^{#1}\fi