It is with deep sorrow that we announce the passing of our friend and colleague Paul Tarau, a brilliant and endlessly curious mind in logic programming whose career spanned the full spectrum from theory to practice.
Creator of BinProlog and LogiMOO, a pioneer in lightweight Prolog-based web processes and extended-precision number representations, and in recent years an explorer of the meeting point between logic programming and large language models, Paul continually pushed our field to evolve and adapt.
His collaborators and colleagues knew him equally for his technical originality — papers that made readers say “I had not thought of this” — and for his generosity, kindness, and steady support of others through difficult times.
Facing illness with remarkable resilience, humor, and lucidity, he remained professionally active far beyond what doctors had predicted, “well past his expiration date,” as he wryly put it. The testimonies gathered below, written by colleagues around the world during his hospital stay, are republished here as a tribute to his legacy and a lasting record of the affection and respect he earned across our community.
By Veronica Dahl (also on behalf of the PEG 2.0 community)
P.S. Here is link to a web site organized by his family: PAUL TARAU
Dear Paul,
Before our PEG meetings, I knew you only through your publications and your outstanding reputation for work on the theory and practice of logic programming. However, through our interactions in PEG, I have gained a much deeper appreciation not only for your technical brilliance but for your collaborative spirit. I especially value your profound insights into integrating logic programming with LLMs. Your work helps us bridge the gap between two disparate modes of computational thinking, reconciling them into a unified whole. Thank you for your immense contributions and for shaping a future where human logic and artificial intelligence can truly work in partnership.
Warmly,
Bob Kowalski
Dear Paul,
Only now have I become aware of your fight with leukemia. I have always admired your papers for their originality, many times wondering “I had not thought of this”. You will not be forgotten.
A big hug,
António Porto
Dear Paul,
I was shocked and saddened to learn that you are battling leukemia. Our paths crossed at SFU some 30 years back when we were visiting Veronica. Admired your many practical contributions in those years – binprolog, logimoo, etc. Will always remember your kind and gentle way of communicating. With prayers and best wishes for your recovery,
Bharat Jayaraman
Dear Paul,
I heard from the PEG group that you are nearing the end of your span on this earth.
Perhaps a little gallows humor: I remember some comedian commenting on the death of a famous person after hearing several obituaries. He said that it was a real shame that he hadn’t held on just a few days longer so he could have heard all the wonderful things people said about him.
So I thought I’d not wait. I have always had the utmost respect for you and your work. I remember your early work with BinProlog and the light-weight Prolog processes you used to manage web interactions. I remember a workshop paper (I think ciclops) where you described an extended precision number representation that I found fascinating. I went back a couple of times to look at it, hoping I’d understand it well enough to implement. But never did… And your recent work with Prolog and LLMs. You’ve always been on the forefront with new technology, figuring out how logic programming can bring something interesting and valuable to the newest technology environment. Your work has spanned the widest range from the most theoretical to the most practical.
I will miss you and your always interesting contributions to our community and meetings. You were always willing to lend a hand and support us all.
Godspeed.
David Warren
Dear Paul,
We have never met in person, but listening to what you say in our PEG-online-sessions, I’ve learned so much, and reading your papers is such a great inspiration. Thank you so much for sharing your thoughts. Your work has so much to offer for the future.
I am thinking of you and wish you comfort and strength.
Christian Jendreiko
Dear Paul,
I first want to say thank you for your patient and persistent lessons, especially those directed to extending this field we feel ours to reach new levels and wider spaces. I confess I get very nervous with your situation, not only because one does not know how to help, but because we are formed in this scientific, objective way of thinking, that turns into a close form of thinking on these issues. I do wish that the medical team attending you finds a way to open possibilities and make you healthy again.
Grateful,
Jacinto Dávila
Dear Paul,
I am writing to you today with a profound sense of gratitude and admiration for the incredible journey you have shared with the scientific community. Your work in Logic Programming means both rigor and creativity leading even to a performant BinProlog implementation. But I think that, beyond your technical brilliance, your greatest impact has been your spirit. The fact that you continue to work with such passion and lucidity today is simply the ultimate expression of the “unwavering excellence” that has always been your trademark. You have taught us that logic is not a cold instrument, but a vibrant, living art form. Thank you, Paul, for your brilliance, your courage, and for showing us all what it means to live a life of purpose. We are all thinking of you with the highest regard and deepest affection.
With all my respect and solidarity,
Fernando Sáenz-Pérez
Dear Paul,
We have known each other for such a long time, and throughout all these years, I have always admired not only your work but also your human warmth. You have always been a true visionary, sometimes bold enough to risk being wrong, but often able to see much farther ahead than most of us.
Do you remember when I bought BinProlog? What I have valued most in your work is your deep intuition that logic programming can only truly live and grow if it keeps evolving and adapting to the world, rather than remaining fixed in its original form. That insight has stayed with me.
I won’t say that I will miss you, because I feel that what you have given, your ideas, your spirit, your way of thinking, will continue to be with me, and with many others, in a very real way.
I wish you a gentle journey, wherever you are going. May it be filled with light, clarity, and the same bold curiosity you brought into this world. Thank you for what you have given to all of us. Safe travels, my friend.
With love,
Stefania Costantini
Dear Paul,
I would like to share a few words that may help you in these emotionally heavy moments. I imagine you may be experiencing a mixture of feelings that only you could truly describe. Please know that there are many people who would like to tell you good things, even if they do not always have the opportunity to express them.
You are truly an example to follow, inspiring us and showing what it means to be both an outstanding scientist and an exceptional person. Your intelligence, creativity, rigor, practical vision, honesty, and serenity—so evident in the way you communicate your ideas—together with your curiosity and openness to new challenges, have kept you at the frontier of knowledge.
This legacy will remain in the collective memory of the scientific community and beyond. Thank you, Paul, for the precious legacy you leave us and for being a guide, both as a scientist and as a person. You have our full support, affection, respect, admiration, and whatever you may need during this time.
Pedro Lopez-Garcia
Dear Paul
I have been always impressed by your contributions and their originality.
They will not be forgotten.
I would like to express my solidarity with you, and wish you strength, peace of mind and comfort.
Włodek Drabent
Cher Paul,
I have been dreading this moment from the time in which, doctors having given you only two years to live, you asked me to present your paper for you at ICLP 2012. Since, the resilience and determination that have kept you happily with us, as you humorously put it, well “past your expiration date” ended up convincing my reptile brain of your immortality :-). So when the news hit, so did Maria Elena Walsh’s words: “aunque hayamos envejecido/ siempre el dolor parece recién nacido”. I found it impossible to write here at the time because that part of my brain did not actually believe, still doesn’t quite believe the news.
Did I ever tell you how hard it was for me to study enough to present your paper half decently? If not, you probably figured it out from all the questions I had to bombard you with until I more or less got it. With your characteristic depth, curiosity and blending power, you’d moved well beyond the subjects we’d researched together. I’ve always admired that scientifically itinerant quality in you, which does not even sacrifice depth or rigor in its eagerness to learn and exploit what’s new. And the fluid sense of opportunity which turned even mistakes into successes.
Once you wanted us to submit to conference X, and I only noticed its deadline’s imminence before heading to a museum with a carful of little girls. I printed the call, which inspired an idea that I sketched in that museum, then wrote the first draft while the kids slept. The following morning I got from you: a teasing notification that I had actually addressed a different conference Y, to which we hadn’t even intended to submit; a section about implementation to add to my draft; … and an almost finished other draft for conference X, which I then contributed to in a hurry before we submitted both. They were both accepted.
What I think I never thanked you for (because I only reflect on it now, with the distance of old, semi-retired age) is how much you helped me survive scientifically when I was sandwiched between single parenting, a demented mother in my sole charge, and an impossibly exacting teaching/research/admin job. The fruitfulness of our collaborations kept me afloat in the Publish-or-Perish seas I had feared drowning forever in. And I could always count on you to do the traveling and presenting for both of us when -as was usual then- I could not.
My heartfelt THANKS my dear friend, for being there for us all these years; for your multi-dimensional scientific contributions; for all the work you’ve done for our LP and PEG communities; for all the interesting ideas you leave for us to complete as we can; and last but not least, for your wonderful sense of humor and your calm, reassuring voice.
Wishing you and your family the best, always. Timelessly :-).
Verónica Dahl