Prof. Dr. Heiner Müller-Merbach (1936-2015)

Heiner Müller-Merbach (1936-2015)

Professor Heiner Müller-Merbach, a highly esteemed operational researcher, passed away on 30 May 2015.  An arm and six ribs were broken when he fell on his porch in December 2013.  Encouraging mails received half a year later, however, left an impression of optimism and recovery.

Around 1 May 2015 he fell again, pre-sumably on his back. A first medical in-spection did not show any severe injuries, and he even joined a birthday party of one of his best friends in that week. Some days later problems with breathing must have begun, most likely as a consequence of the fall because it turned out later that his lungs were injured. Unfortunately, like other shy men, unwilling to talk of their health, he tended to retire in such situations; maybe because he did not want to bother anybody or did not want to admit that he needed help.

A physician and close friend of his realized the situation and had him immediately admitted to a hospital where he received surgery. On the day after it was difficult for him to move and to speak, which was a shock to his family. His condition kept worsening and after one week in the hospital his heart stopped beating.

Heiner complained from time to time about getting older and opposed vigorously the mere thought of being disposed of in a nursing home. Thus, although untimely, it is a gift of grace to ‘shuffle off this mortal coil’ in the way it happened after having enjoyed a rich life without suffering the horrors of old age and, even more so, to preserve both a warm heart and a brilliant mind to the end.


IFORS Past Presidents (L to R), Heiner Muller-Merbach (1983-85,Germany), Brian Haley (1992-94,UK), Peter Bell (1995-97,Canada), Elise del Rosario (2007-09, Philippines), Andres Weintraub (1998-2000,Chile), Paolo Toth (2001-2003, Italy) and Thomas Magnanti (2004-06, USA) on the occasion of the 50th Anniversary of IFORS celebrated in Sandton, South Africa, July 2008.

Outline of an outstanding academic career

It is way beyond the scope of this obituary to provide an assessment of Professor Müller-Merbach’s scientific achievements. Instead let the facts speak for themselves as expressed in Lebenslauf, a 1-page CV in German prepared by Heiner himself and to become excerpted here. TH and TU are the German abbreviations for Technische Hoch-schule and Technische Universität, respect-ively, both self-explanatory to readers of a text in English.

Born on 28 June 1936 in Hamburg where he lived until graduation in 1955 from the upper secondary school (Arbitur). 1955-1960: Studies at TH Darmstadt (Diplom-Wirt-schaftsingenieur). 1962: the Dr. rer. pol. degree was earned at TH Darmstadt. 1963-1964: post. doc. at Operations Research Center, University of California, Berkeley; Head of department: George B. Dantzig. 1967: Habilitation at TH Darmstadt. Since 1967: Professor of Betriebswirtschaftslehre and Betriebsinformatik at Universität Mainz (1967-71); at TH Darmstadt (1972-83); and at TU Kaiserslautern until his retirement in 2004. 1974-76: Vice President of IFORS. 1983-85: President of IFORS. 1986: Honorary Professor at Tongji University, Shanghai. 1988: Companion at Operations Research Society, UK. 2002: Fellow of Institute for Operations Research and the Management Sciences (INFORMS), USA. Publications since 1961: 14 books, 2 CD-ROMs, about 450 other writings. 1985-87: Editor-in-Chief of technologie & management. Editorial Board Member for 15 professional journals.

It is commonly believed among academics that the promotion to the rank of full professor is the top of an academic career. But there is still a step on the ladder to be climbed: to become an emeritus. Maximum maximorum! Professores emeriti enjoy cer-tain privileges but nobody can impose duties upon them anymore; there is full freedom to select from the menu and say yes or no to whatever is suggested. Heiner was indeed aware of that as evidenced by a document, The life of an emeritus!, circulated to his friends in January 2009. In his own words: Isn’t it good to have a few modest plans? I like them, each single one with full en-thusiasm. That is my only problem, and I start every day with an internal dispute about the priorities. That keeps me going. But I must always think of the Amish wisdom: “The hurrier I go, the behinder I get”.

The remainder of this obituary must inevitably be split into two parts since the authors’ gateways to Heiner, as reflected by our respective affiliations, are different. Hence, the same applies for our personal recollections.

Colleague and friend (Jakob Krarup)

My very first meeting with Professor Müller-Merbach and several other notables within mathematical programming dates back to “Large-scale resource allocation”, a NATO-sponsored conference held in Elsinore, Denmark, in 1971. George B. Dantzig and Richard W. Cottle were in charge of the scientific programme while all local matters were delegated to me.

We addressed each other rather formally in the beginning as it was a habit at that time and still is in, for example, a German-speaking environment. After a year, however, during a coffee break between two lectures, Professor Müller-Merbach grabbed my arm and said “call me Heiner”.

A lasting friendship evolved along the way and extended soon to encompass all members of my family. In particular we learnt to appreciate his truly outspoken sense of humour! Since the mid 70s Heiner was a frequent and very dear guest at my home. Similarly, several visits have been paid over the years to Am Löwentor 11, his home in Darmstadt, amongst others equipped with two wine cellars and conveniently located for stop-overs en route to/from visiting ap-pointments with Swiss or Austrian universities.

Furthermore, as passionate number freaks we have exchanged numerous challenging writings but never considered joint papers as our close cooperation largely dealt with the organisation of conferences and work as editorial board members for various journals; the latter starting with the 1st Editorial board meeting of EJOR, held in Paris on 21 June, 1975.

There are several anecdotes to be told about Heiner of which some belong to the more private sphere. But the following two may possibly serve as apt illustrations of our relationship.

Heiner enjoyed good meals, wine and beer, preferably with lively company around him at the dinner table. As an unhappy side effect, however, he once gained weight, unfortunately to an extent which prompted his family to send him for a 1-week cure in Sweden. Water from a well, beetroot juice, stewed vegetables and other disgusting things. He was almost starving when he stopped by at my home on his way back to Darmstadt. “Ah”, said my wife when the family gathered at the dining table, “I have prepared a nice roasted pork with lots of crackling, all accompanied by an exquisite Bordeaux. Not to ruin what you have endured in Sweden, however, I have cooked a good vegetable soup for you and here is a jug of water to go with it”. Heiner remained remarkably brave for quite a while until he eventually threw in the towel: “Can I taste just a little bit of the pork?” A little bit is but the thin end of the wedge. We stayed for hours at the table. More wine was uncorked. Leftovers from the pork were meant to be served for other guests on the day after. But all vanished like dew before the sun.

Beijing Airport, prior to our departure for Europe after having attended IFORS 1999. Heiner: “We are on different flights. Give me a nice brain teaser I can play with en route to Frankfurt.”. Me: “Does there exist a number x = 11111 … of ones only having 1999 among its divisors?”. Heiner, upon his return: “Your puzzle was quite tricky but it appears that any prime n (save for n=2 and 5) is a divisor of 11111 … , and the number of ones equals the period length of 1/n.”.

Heiner liked to emphasize that he was much older than me, 24 days, to be very precise. At a birthday symposium titled “1936: a vintage year for OR” he delivered a humorous speech, embarking from 1936 being the only 4-digit square number starting with 19. I believe it was in conjunction with that event he also reported on a recent garden party:

To protect his home from burglary Heiner had installed a rather complex alarm system with sensors everywhere, connected with sirens and projectors. Suddenly, in the middle of the night, the sirens could be heard all over the neighbourhood and the garden was flooded with light. Attracted by the unusual noise numerous neighbours woke up and invaded the garden to assist Heiner in his search for the prospected intruder. But, as no such intruder was found, and as kind of compensation for the neighbours’ efforts, Heiner had to dive down into his wine cellar to serve them all. A lively garden party with very thirsty guests emerged!  It was also explained what had caused the alarm: a cat had apparently sneaked in via a window ajar.

Operational research, managerial prob-lems, the intractable integers, and numbers in general: we were never short of subjects in discussions  related to our main field.  But also a wide variety of other aspects of the humanities occupied Heiner’s mind. Thus, the visible result of his deep interest in philosophy was the appearance in 1991 of Philosophie-Splitter für das Management.  “Why ‘für das Management’?”, I asked. “Well”, Heiner replied, “this is meant to be an appetizer for potential buyers who normally associate my name with man-agement. Thus, increased sales are hoped for”.

Heiner would have turned 79 on 28 June 2015. No more congratulatory notes spiced with numbers to become exchanged on our birthdays. No more mails closing with ‘artige Handküsse’ for my wife will be received.  Also the tradition at conferences, also attended by my wife, to have a last evening meal just for the three of us must henceforth become but a fond memory.

IFORS (Helle Welling)

I cannot talk about Heiner’s profound O.R. knowledge and insight, his play with numbers, his great mathematical skills, et cetera. I can only admire these skills. But I have worked with Heiner in a myriad of IFORS situations and have memories of both difficult and fun ones.

Heiner’s son, Dr. Jens Müller-Merbach, told us that Heiner had already started making plans for his 80th birthday in 2016, and it saddens me that this event could not be realised. I would otherwise have liked to have expressed the following to Heiner:

“Dear Heiner: Since 1972 I have had the privilege of knowing you and working with you in many IFORS capacities. In 1972 the IFORS Triennial Conference was held in Dublin and you were the Programme Committee chairman. The Dublin Conference was my first meeting with the IFORS world, and by watching you and studying the programme I got an idea how the Programme for a Triennial Conference was structured. In 1974 you became a member of the IFORS Publications Committee – with your love for words and numbers this was really a task up your alley -, then IFORS VP 1974-1977, member of the Organising Committee for the 1981 IFORS Conference in Hamburg, President 1983-1986 and, subse-quently, Immediate Past President.

I particularly recall a very special task the IFORS Administrative Committee (AC) had asked you to carry out in 1982. The Com-mittee had met in Lausanne, Switzerland, and on the agenda was a possible change of location of the 1984 IFORS Triennial Conference. This was before e-mails and cell phones, et cetera. Late in the evening you telephoned the Organising Committee Chair-man and conveyed the AC’s decision. The whole situation was rather emotional, but you conveyed the message – while the streets of Lausanne went crazy. The very same day the European football champion-ship had reached its final, and the winners drove through Lausanne while they hooted and flashed their lights. This was a rather bizarre situation which you handled with your usual, stoic attitude.

We also worked closely together in connection with the UNESCO funded FIACC – the Five International Associations Coor-dinating Committee – the umbrella for IFORS and its four Sister Federations – IFAC, IFIP, IMEKO and IMACS. Representatives from each Federation met once a year somewhere in Europe to coordinate their various events. You chaired FIACC during the years 1985-1987.

When I think of our working relationship, words that come to mind are:  respect, engagement, involvement, dedication, thoughtfulness, IFORS family. Often during your presidency you called me asking ‘Did I forget something?’ Your thoughtfulness manifested itself by sending me Christmas and birthday presents, and Christmas cards to my family. My son was so intrigued by the way you dealt with numbers in these cards. One of your Christmas presents was a beautiful trivet. I look at that trivet every morning when I place my teapot on it – and am reminded of  IFORS days.

Your thoughtfulness did not stop when I retired from the IFORS Secretariat. Every time you participated in an IFORS or EURO event you sent me postcards from various places all over the world. They were not just ordinary postcards, no, you managed to include signatures from many of my IFORS friends attending the event. Thank you.
By so many people you are thought of as a true gentleman, a sincere friend, and by your IFORS colleagues you are deeply respected for all your OR contributions before, during and after your IFORS presidency. The IFORS Member Societies in particular remember your many ‘Letters from the President’ – your monthly ‘talk’ to the OR world – which at that time was distributed together with the IFORS Bulletin.

The first presidential letter appeared in January 1983 but it was nowhere said that “No. 1” necessarily would be accompanied by more. By issuing “No. 2” only a month later, however, the author has sort of trapped himself: to cover the whole period without reducing speed, 34 more letters had to follow.

On the occasion of your 50th birthday in 1986, Jakob and I suggested that the complete collection of 36 letters deserved a wider circulation. The editors of European Journal of Operational Research (EJOR) were approached and agreed to publish all 36 letters in a single paper. Furthermore, and most appropriately, Jacques Lesourne, the then President of IFORS, was invited to join forces with us in writing the Editorial.

Learning from your son about your plans for your 80th birthday, I was reminded of what I said in the Editorial:

‘Apart from giving his time and his professional and diplomatic talents, I venture to say that Heiner has also lent his heart to the tasks he has been asked to do for IFORS.

Heiner and I have worked together in many IFORS situations ranging as they do from the location of a Triennial Conference to the mixing of a German punch bowl during an Administrative Committee gathering at his house in Darmstadt. I have watched how Heiner always attacks the problems with thoughtfulness, with tenacity of purpose and sincerety. I think that the latter is Heiner’s secret – and his strength.’

What  applied to your 50th birthday also applies to your 80th birthday.


Thanks are due to Dr. Jens Müller-Merbach who in a mail reported on his father’s last days, and to Heiner’s secretary, Ms. Dagmar Schwarzer, who provided us with the link to the family.


J. Krarup, J. Lesourne, and  H.R. Welling,  “Editorial to ‘Letters from the IFORS Pre-sident’”, EJOR 25 (1986) 421-422.