Kenneth I. Appel
Tasker Funeral Home - Dover
621 Central Ave
Dover, NH
Kenneth Appel

DOVER - Kenneth I. Appel, 80, of Dover, a member of the city's school board since 2010, died Friday, April 19, after a short hospitalization. He had been diagnosed with esophageal cancer in October.

He chaired the mathematics department of the University of New Hampshire from 1993 to 2002, retiring as professor emeritus in 2003. From 1961 to 1993 he was a mathematics professor at the University of Illinois, where he and his colleague Wolfgang Haken solved one of the most famous problems in mathematics: the Four Color Conjecture. They answered this question: could it be proved that any map can be colored with just four colors so that contiguous countries have different colors? Their proof that four colors were sufficient, announced in 1976, was the first major mathematical theorem to be proved with the aid of a computer.

Kenneth Ira Appel was born in Brooklyn, N.Y., on October 8, 1932, and grew up in Queens, N.Y., the son of Irwin Appel and Lillian Sender Appel. He received a bachelor's degree in mathematics from Queens College in 1953. After working briefly as an actuary, he served two years in the U.S. Army, at Fort Benning, Georgia, and in Baumholder, Germany.

He received his Ph.D. in mathematics from the University of Michigan in 1959. In Philadelphia that year he married Carole S. Stein. They moved to Princeton, N.J., where Ken worked for the Institute for Defense Analyses, doing research in cryptography. After joining the University of Illinois at Urbana he taught mathematics, did research on group theory and computability theory. He served on the Urbana city council and later on the city's zoning board.

The New York Times wrote in 1976, "Now the four-color conjecture has been proved by two University of Illinois mathematicians, Kenneth Appel and Wolfgang Haken. They had an invaluable tool that earlier mathematicians lacked - modern computers. Their present proof rests in part on 1,200 hours of computer calculation during which about ten billion logical decisions had to be made. The proof of the four-color conjecture is unlikely to be of applied significance. Nevertheless, what has been accomplished is a major intellectual feat. It gives us an important new insight into the nature of two-dimensional space and of the ways in which such space can be broken into discrete portions."

In 1979 the American Mathematical Society and the Mathematical Programming Society awarded the Delbert Ray Fulkerson prize to Appel and Haken. In 2012 he was elected a Fellow of the American Mathematical Society.

Ken Appel was passionate about mathematics education, at all levels from elementary school to graduate school. At every stage of his life, he sought opportunities to teach - as a graduate student in Michigan, as a volunteer lecturer at Princeton University, in more than fifty years as a professor, and in retirement as a volunteer in mathematics enrichment programs in Dover and southern Maine public schools. He particularly believed that students should be afforded the opportunity to study mathematics at the level of their ability, even if it is well above their grade level. To that end, he enjoyed working with gifted high school students on the kind of math problems he would give to his graduate students.

He was treasurer of the Strafford County Democratic Committee. He was an avid tennis player until his fifties, a lifelong stamp collector, a skillful player of the game of Go, a baker of bread. He was a loving husband, father, and grandfather.

Kenneth Appel is survived by his wife Carole S. Appel, son Andrew W. Appel and his wife Maia Ginsburg, of Princeton, N.J.; son Peter H. Appel and his wife Bárbara Zamora-Appel, of Alexandria, VA; sister Lois Green of Henderson, Nev., and her husband David Green; nephew Douglas Green and niece Lisa Bouley; by five grandchildren, Avi and Joseph Appel, Rebecca and Nathaniel Weir, and Carmen Appel, and by his brother-in-law Howard Stein and his wife Lea.

Carole and Ken's daughter Laurel F. Appel, a biologist at Wesleyan University, died on March 4 this year at the age of 50 and is survived by her husband, Michael P. Weir.

Contributions in Kenneth Appel's memory can be made to the Laurel F. Appel Fund for Student Research, Wesleyan University, c/o M. Herlihy, 318 High St., Middletown, CT 06459, or at, specifying that the gift is for the Laurel Appel fund.

Funeral services will be on Monday, April 22, at 10 a.m., at Tasker Funeral Home, 621 Central Ave. Dover with visiting at 9:30 a.m. and burial at Pine Hill Cemetery.

Please go to to sign the online guest book.

Visit for an online guest book.

Published by Foster's Daily Democrat from Apr. 21 to Apr. 24, 2013.
To plant trees in memory, please visit the Sympathy Store.
To offer your sympathy during this difficult time, you can now have memorial trees planted in a National Forest in memory of your loved one.
Funeral services provided by:
Tasker Funeral Home - Dover
Add a Message

Not sure what to say?

34 Entries
My day is improved by the memory of Ken. Much love Carole.
Burt Cohen
April 14, 2020
So sorry to hear of Ken's son graduated from DHS in 2012 and was privileged to work with him..Josh is now at Harvard...feel very blessed that he had the opportunity to work with such a brilliant mind...our sympathies to your family and thank you...The Bean family
Anne Bean
May 13, 2013
In recent years, I have been making pizza for my family. Every time I make it, I think of the great parties we attended at the Appel house on Pell circle in Urbana, where Ken would make pizza for everybody - ken's pizzas me this idea. I use organic ingredients in proportions that are far more healthy than commercial pizza, so that my kids can have long lives. Thank you, Ken.
Donald Gillies
May 10, 2013
Dear Carole,
We want to express our sadness on hearing the news about your husband Ken. Upon reading Ken's obituary we also found out about your daughter Laurel. Our thoughts are with you at this difficult time. We fondly remember your family being part of our Urbana neighborhood.
Bill and Eileen Kohen
May 9, 2013
My condolences to the Appel family. I was one of Dr. Appel's students at UNH and I was struggling in his class. He took the time to sit with me and never once did I feel stupid. In fact, it inspired me to complete my degree. He truly was one in a million.
Brandy Gagnon
May 8, 2013
My local paper in my very small town in Southern Illinois listed Professor Appel's death because of his fame in proving the four color theorem. I had Prof Appel my first semester at U of I for Honors Calculus III. He was an engaging and enthusiastic professor, who clearly loved mathematics, and probably was one reason I decided to major in mathematics. For years our mailings from the mathematics department proclaimed: "Four Colors Suffice."

I went on to law school because I was not cut out to be a mathematician, but Professor Appel is the only math professor whose name and memory has stayed with me. I am sorry for the family's loss, but grateful I had the opportunity to extend to his family my good memories of him.
Judy Cape
May 1, 2013
I worked for Prof. Appel when I was a CS graduate student at UIUC working my way through school as a unix system administrator for the Math department. He was kind and humble with a down to earth approach to his work. I fondly remember him learning PostScript and occasionally (if I wandered by his office) being asked to help him debug programs. It was a helpful example for me, a very intimated first year graduate student, to see someone so smart asking for help.
Robert Zeh
May 1, 2013
I am sorry for your family's loss. My condolences. Was Mr. Appel related to a Gunther Appel of Potsdam or Nedrow NY? I ask because Gunther was my grandfather and his mother, Ethel lived in NYC. Never knew any of his family.
Brenda Appel Germain
April 29, 2013
Dear Carole and family:
My daughter, Virginia Towler, and I were very sorry to hear of your husband's death. I had just met him at the FDR dinner. May you be comforted by friends who love you.

With deepest sympathy,
Carmen Buford-Paige
Carmen Buford-Paige
April 24, 2013
Dear Carole,

I was shocked and saddened to read of Ken's death. You have all my sympathy and best wishes. Love, Susan Koppelman
April 24, 2013
Dear Carole and family,
I am sending you my heartfelt condolences at the passing of Ken. His obit reveals a man of science, and brilliance. And yet, he used those gifts to teach. It says so much about him. May you find peace and comfort in your time of mourning.

With heartfelt sympathy,
Honorable Kim Casey
kimberley casey
April 24, 2013

May you find comfort in the love and support of friends and family.
Gary & Lenore Patton
April 23, 2013
Dear Carole and Family--

You have our deepest condolences and heartfelt sympathy. You are in our thoughts at this difficult time.
Anita & Greg Hattiangadi/O'Neill
April 23, 2013
Peter, andrew, and carol : my deepest sympathies go out to your family this year. Ken lived a long life and certainly lived up to his potential like few others. Thank you for the great biography - it was an inspiration. In time I hope you will be able to appreciate being together as a complete family for almost fifty years. That is a wonderful gift to your lives that few others in our Urbana neighborhood have enjoyed.
Don Gillies
April 22, 2013
Dear Carole and Family,
I am sorry not to have been able to attend this morning. Ken and Laurel were both generous, intellectually vibrant, admirable people whose conversation was filled with insights and whose company was a treat. One of summer's pleasures was to have them visit. They are missed.
Patricia Emison
April 22, 2013
May your hearts soon be filled with wonderful memories of joyful times together as you celebrate a life well lived.
Cheryl Goscinski-Drew
April 22, 2013
Dear Carole & Appel Family:

My wife and I send our deepest condolences to you at this time. Ken was a wonderful and caring man who touched many people's lives. He was an inspiration to me as a mathematician, an educator, a citizen, and a human. I shall be listening to Tom Lehrer sing the derivative song in his honor, in perpetuity.
Ian Cooke
April 22, 2013
Dear Appel family,

I am sad for your loss, and will miss Ken. His patient attention to his students at UNH will be remembered fondly.

Jon Bannon, former student
Jon Bannon
April 22, 2013
Mr. Appel was a wonderful contribution to our community. An honorable and compassionate man who will be missed. Thank you for allowing him to have the time away from his family to serve our community.
Pati Frew-Waters
April 22, 2013
Gisele and I are sorry to hear of Ken's passing. You and your family are in our thoughts and prayers. I will always remember Ken's gentle smile while walking one of his favorite dogs past the house.
Gisele and Bernard Tisserand
April 21, 2013
Carole and family: My condolences and prayers are with you. Ken was a very quiet,reserved gentleman who listened intently and studied all of the educational issues that pertained to the children of our City.When the moment arose,he would quietly interject his thoughts that would always carry so much educational weight for a student. He gave of his time within the classroom, assisting the staff to reach a very important goal for him;that each child have an opportunity to do his/her best. He will be missed by the children, the staff, the School Board and most importantly- the community. He served us all well in his desire to volunteer his knowledge and his help. His memory will linger in this City for years to come.
Doris Grady
April 21, 2013
Dear Appel family,

I will miss Ken, and will always have vivid and fond memories of him. His support of young mathematicians was inspiring. Whether it was seeing him regularly working with middle-schoolers in his office on mathematics, or being taught by him how to actually make coffee (rather than waiting like a vulture for somebody else to make it in the department), Ken's patient attention made me proud to be part of the mathematics community. I had the good fortune of seeing him speak here in NY at Skidmore a few years ago, and then joining everyone for dinner afterward. I had a million things to ask him after that talk that I decided to wait to ask him the next time I saw him. I should not have waited. I'm very sad today about his loss. I'll always remember him. My deepest condolences to you in your loss.
April 21, 2013
I am so sorry to learn of Ken's passing. I will keep you in my thoughts and prayers. I will also pass along the sad news to my colleagues at UNH who knew and admired Ken.
Janet Campbell
April 21, 2013
Dear Appels,

I will miss Ken's spirit, compassion, and humor.
Neil Portnoy
April 21, 2013
To the Appel family,

My condolences upon Ken's passing. His dedication to the education of the area's school children and his community will not be forgotten.

You are in my thoughtsand prayers.
Jason Hindle
April 21, 2013
As a student of his in the Dover School District, I'd like to say that he was and still is my inspiration. I am truly grateful for everything he's done, not only for me but for the whole school district. He will be greatly missed.
Junha Kim
April 21, 2013
To the Appel family, cornerstone VNA send our deepest sympathy on the loss of Kenneth . our thoughts and prayers go out to all of his family and friends ...
Cornerstone VNA
April 21, 2013
So sorry to learn of this.
May his memory be a blessing.
Burt Cohen
April 21, 2013
Dear Carole,
The entire End 68 Hours of Hunger team send our most sincere wishes for peace and comfort for you and your family! You and Ken have been the backbone of so much of what we have been able to do in Dover, and he will be truly missed!

Claire Bloom and Keith Launchbury, Dover
April 21, 2013
Dear Carole our thoughts and prayers are with you.
Charlotte, Bill Caldwell
April 21, 2013
Dear Appel Family,

I am saddened to hear of Ken's passing. Ken was a huge advocate for our students and he always kept them at the forefront when making decisions. Ken was a man who spoke sparingly but with great reason and understanding. His absence in the community and our schools will be acutely felt but we are better for having known him and for having had his guidance.

I know I speak for all of Dover High School when I say that we are thinking of your family during this difficult time, and we thank you for having shared Ken with us for so many years.
CHristine Boston
April 21, 2013
Dear Appel Family,

I worked for Ken when I was in college. His heart and love for his students was felt, and he will be missed greatly by many.

Barbra Bannon
Barbra Bannon
April 21, 2013
On behalf of the Dover High Mathematics department, we offer our condolences to the Appel family. We will miss Ken dearly and truly appreciate all that he did for the students of Dover.
April 21, 2013
Dear Appel Family,
I am very sorry to hear of Ken's passing. He was a strong supporter of our schools and the teaching of math to our students. Ken did not say a lot in public but when he did, his few words said volumes. The Appel family are in my, and Woodman Park School's, thoughts and prayers.
Patrick Boodey
April 20, 2013
Showing 1 - 34 of 34 results