What are the Hergert Numbers?

Posted on Nov 25, 2014

Famous mathematicians have famous concepts named after them.  The Pythagorean Theorem, The Fibonnaci Sequence, Boolean Algebra and the Hergert Numbers to name just four.

Wait.  You probably know who Pythagoras was.  Fans of The Big Bang Theory have probably heard of Leonardo Fibonnaci is, and George Boole is well known.

But who is the mad genius behind the Hergert Numbers?

Hergert BobbleheadIt’s none other than Rock Valley College Interim Dean of Math, Rodger Hergert.  His claim to the Hergert Numbers started as a flippant comment during a calculus class he was teaching years ago, and has gained steam ever since.

“It was about 20 years ago, and it was the first time I was teaching Calculus,” he said. “When we got to the applications of derivatives, we talked about critical numbers being the potential relative extrema and identified them as points where f'(x)=0 or f'(x) is undefined. In the very next section, we came across possible inflection points that consisted of points where f”(x)=0 or f”(x) is undefined. I was surprised to see that there was no name for these points. So, I began calling them Hergert Numbers. I was just goofing around.  But every time I taught Calculus I’d continue to call them Hergert Numbers.

“In the Spring of 2009, I made that same reference, but added, ‘I’ve been calling them that for 15 years, but it doesn’t seem to be catching on.’  And then a couple weeks later I come into class and the students said, ‘Hey Mr. Hergert, we made shirts!  Here’s one for you and we’re going to help you spread the word.

“So, it was my class that created the shirts.  I found out a couple years ago that they had already decided to do a class t-shirt.  It was a class where the students had really bonded, and it meets five days a week, so they see each other a lot.  They had become pretty good friends.  Apparently after I made the comment they said ‘that’s it’ and they made the shirts.”

Students made and sold shirts for the next two years to help spread the word, and for Rodger’s birthday they gave him a Hergert Numbers hat.  Since then, he’s been the one arranging to have shirts printed and delivered.  When asked where the proceeds from the shirts go, Hergert laughs and says sheepishly, “If there were some, probably to a scholarship.  But I actually take a loss on them.”

Hergert gets requests from students at other colleges for the t-shirts and some instructors give extra credit for students who wear the shirt to class.  He delivered a dozen just this summer to students at the College of DuPage.

The newest addition to Rodger’s personal Hergert Numbers merchandise is the Hergert Numbers bobblehead.  This one of a kind (OK, there are actually two of them in existence) bobblehead was a gift from his wife Deena.

Hergert Merch

A visit to the official Hergert Numbers website not only has the explanation for exactly what the numbers are, but also includes Rodger and others proudly posing in Hergert Numbers t-shirts at famous locations (Niagara Falls, the Grand Ole Opry, etc.) around the country.  The site also includes an e-mail address where you can send in your very own Hergert Numbers t-shirt order.

Has the Hergert Numbers made it into any Calculus textbooks yet?  Let’s just say it’s getting there.  “I was at a conference and the man who writes the Calculus text we use, and that many colleges all over the country use, Ron Larsen was speaking,” Rodger said.  “I went to his keynote and thought I could chat with him afterwards about it, but he was in a hurry to go.  I guess he’d flown into Champaign just for the speech, and actually had his driver wait for him in the parking lot.  But I had a chance to talk quickly to him.  A few weeks later he called me, and said that while he wasn’t ready to put it in the text, he really liked the concept and links to the Hergert Numbers from the website for the book.”

Sure enough, if you go to larsoncalculus.com when you get to the section (it’s in chapter three) that deals with possible inflection points you get a link to hergertnumbers.org.

Visit the Facebook page for Hergert Numbers to see RVC students (and students from other colleges) wearing the shirt, to see people wearing the shirt in famous locales, and even to read about a Hergert Number wedding.  The concept continues to catch on.

“A couple of years ago I was in Jacksonville, Florida for a national conference,” Rodger says.  “I was talking to some professors from Illinois and Kansas and after a few minutes someone from Kansas looked at me and said, “Oh, you’re that Hergert?” 

And we can all say we knew him back when.