mjo-common: add \lcm{} for the least common multiple.

diff --git a/examples.tex b/examples.tex
index 0cf8afa51a90a84b624fee9a7f4232ae7ff9a52d..131a213b5a465894f7691edf546952e676c2e8b1 100644 (file)
--- a/examples.tex
+++ b/examples.tex
@@ -98,7 +98,9 @@
       \end{item}
     \end{itemize}
     %
-    The factorial of the number $10$ is $\factorial{10}$.
+    The factorial of the number $10$ is $\factorial{10}$, and the
+    least common multiple of $4$ and $6$ is $\lcm{\set{4,6}} =
+    12$.
 
     The direct sum of $V$ and $W$ is $\directsum{V}{W}$. Or three
     things, $\directsumthree{U}{V}{W}$. How about more things? Like

diff --git a/mjo-common.tex b/mjo-common.tex
index 284d5a5fe9460a2ef4e32c7e5c5320784f0402fd..041a1eb604a1bb753ba5b8415098d4f310fecc4d 100644 (file)
--- a/mjo-common.tex
+++ b/mjo-common.tex
@@ -39,6 +39,18 @@
 % A seven-tuple of things.
 \newcommand*{\septuple}[7]{ \left({#1},{#2},{#3},{#4},{#5},{#6},{#7}\right) }
 
+% The "least common multiple of" function. Takes a nonempty set of
+% things that can be multiplied and ordered as its argument. Name
+% chosen for synergy with \gcd, which *does* exist already.
+\newcommand*{\lcm}[1]{ \operatorname{lcm}\of{{#1}} }
+\ifdefined\newglossaryentry
+  \newglossaryentry{lcm}{
+    name={\ensuremath{\lcm{X}}},
+    description={the least common multiple of the elements of $X$},
+    sort=l
+  }
+\fi
+
 % The factorial operator.
 \newcommand*{\factorial}[1]{ {#1}! }