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Thank You Page

First, I want to thank everyone that reads the posts, and also those who take time to make comments. Thank you very much.

Second, I want to thank my two graduate students, Subrahmanyam Kalyanasundaram and Farbod Shokrieh, who have helped in numerous ways to make this blog possible.

33 Comments leave one →
  1. Yousef Hatem permalink
    March 11, 2010 9:20 am

    Thanks Professor.

    I’m a TA in this course, your articles shed some light on this interesting field of theoretical CS.

    I’ve Emailed your blog to my Professor.


  2. May 19, 2010 7:31 am

    I love your blog. I study this stuff in my spare time and I’m still only a junior in highschool. You’ve made me want to start blogging about this stuff too–I’m only starting out.

    Anyway, I look up to you and your intellect! Keep up the good work!

    • rjlipton permalink*
      May 19, 2010 8:48 am


      A junior—cool. Let me know how I can help.

  3. June 11, 2010 5:54 pm

    terrific blog! I’m an English teacher who likes to nerd out to math every once and a while – your site fulfills the need for elegant rationality in a world of inelegant chaos [praise ad nauseum]

  4. Anonymous permalink
    July 20, 2010 12:05 pm

    Your posts are fascinating and truly insightful.

    I was wondering if you’d like to create an article on Prof. Mulmuley’s GCT approach.

  5. August 13, 2010 12:04 am

    I would like to notify on ur new posts..

  6. Ma, Zhengrong (马峥嵘) permalink
    August 18, 2010 2:59 pm

    Thank you for your effort. I studied this topic back several years ago when I was in graduate school. I love reading progesss in this field.

    ps. the Chinese translation of this blog works not so well. Is machine translation NP diffcult?

  7. alienintheheights permalink
    August 19, 2010 11:35 am

    Richard, I am so grateful for your blog and the coverage you facilitated during this recent media storm. I earned my Master’s in Mathematics twenty years ago but have since worked in the software world. These conversations have inspired me to start studying the mathematics behind this topic in detail. I look forward to reading your future posts.


    • rjlipton permalink*
      August 22, 2010 12:56 pm


      Thank for a very nice comment. Thanks.

      dick lipton

  8. Shannon Sequeira permalink
    September 14, 2010 3:16 am

    I sincerely admire your work. I’m only 15, and still in high school, tidbits and core ideas are still accessible. Thank you so much for blogging here, you’ve opened up a whole new field for me to explore.

    The only complaint is that I have is that there is no contact page, hope you add one soon, although if you can, do email me, my address is in the system.

    Thank you for sharing your knowledge with us.

  9. September 28, 2010 12:41 pm

    I greatly enjoyed your blog, which I only found about a week ago. Particularly interesting to me and inspiring was you blog titled “Can Amateurs Solve P=NP?”

    As an amateur physicist and mathematician ( that is someone who devotes a great part of his free time to the subjects for pure enjoyment), I found your words very encouraging.

    Best regards from Montreal,

    Daniel L. Burnstein

  10. October 10, 2010 8:00 pm

    Well, you deserve the biggest thanks. I just want to say thanks for all the effort and time you put into this blog.

  11. k.koiliaris permalink
    November 22, 2010 6:09 am

    Thank you very much for giving us students a chance to see and feel that this field of research is alive and live! It’s a great inspiration for everyone to have such a direct communication with professors such as yourself and everyone else who is posting here over the several scientific debates and conversations.

    If I could ask for one thing, I believe many students, including myself, would appreciate a post on the progress – open problems of the Theory fo Algorithms. Something like a wrap up update of the current vibe and progress.

    Thank you very much for sharing everything with us and creating this online community where we can all interact with people like you.

    Best regards from Oxford,
    Konstantinos Koiliaris

  12. Ravi Dattatreya permalink
    November 26, 2010 5:16 am

    I have been studying the randomized algorithm for finding a Hamiltonian Circut by Angulin & Valiant. I am looking for a similar one which can also apply some constraints of the form “nth visit has to be at node An, kth visit has to be at node Ak,” etc.

    Any ideas?

    Thank you for shaing your thoughts.

  13. Manuel permalink
    April 22, 2011 5:52 am

    I think that this post is absolutely wonderful because it is a good idea to get research known to people who are not working in this field. I believe that research is an unknown world for common people, but I think that it should be shared with all human beings because in my opinion it is a common good. I graduated two months ago in Computer Science in Padua (Italy) and now I am working for an advisory company but this blog makes me feel so close to my accademic past and to research. I have been interested in theory of computation since my professor at university did the first lesson. My dream was (and it is) to become a researcher of theory of complexity but as you can know in Italy research doesn’t work well. Therefore this blog is a way to be informed about new (and old) research topics.
    Thank you again!

  14. May 4, 2012 7:55 am

    Dear Professor,
    Thanks for the nice blog.
    May i send via e-mail my manuscript “the theory of plafales:the proof of P versus NP problem” to your private e-mail that to know opinion about it?


  15. July 5, 2012 3:19 am

    Hi Professor,

    Your content It’s amazing, your blog is really helpful for those who came at this point. I admire your work, I had a blog also about basic programming in various languages as my future references at the same time for the beginners out there to acquire more knowledge about programming concepts.

  16. Ben Dreyzen permalink
    November 25, 2012 5:44 am

    Dear Professor(s),

    I love your blog and wish I was more of an expert (Computer Science and Economics student at UNC Chapel Hill).

    Where might a beginner find a comprehensive introduction or “base” to the theory of computation? I would love to learn more.

    Once again, I love the blog.

    Thanks, Ben

  17. Sonny daniels 3 rd permalink
    November 28, 2012 12:42 pm

    What is the sqaure root of – 1

  18. NoName permalink
    January 15, 2013 5:39 pm

    The awful “follow” popup on your chess article really should be removed, it makes the article unreadable on a mobile. I gave up before I even got to the bit about chess.

  19. May 3, 2013 10:37 am


    I have been a long time follower of your blogs. There has been a lot of buzz around Bitcoins. One of the claims of bitcoins is that it can predictably adjust the “mining problems” difficulty. I don’t have much clarity on how it works. I would really like your take on it.

  20. David permalink
    August 14, 2013 8:13 pm

    I might like to say TY to someone but I must remember that in all equations of physics and or computational math that nothing in current theory relativistic or demonstrative proves anything. The additions of forces weights ,values or waves of magnetism or any other measures to forcibly validate an equation are about the same as the shoving an unwanted Banana up a Monkeys Butt SHAME on You all

  21. Voices in the Rain permalink
    August 26, 2013 10:38 pm

    I dropped in on your Blog in a Google search on Hedy Lamarr. I had been reading about Alan Turing and his work on Secure Speech when I had a vague memory of an actress and a patent. It was like finding a needle in a haystack.
    I looked through the Blog Site a little and decided to Follow after seeing your reference to Rosencrantz and Guildenstern. I have seen the movie and the play once at a summer feast in Snowmass, Colorado. I hope to visit again soon and enjoy your site. I am a sucker for interesting details in life.
    As a child in eighth grade I understood enough of Einstein’s Relativity to know that Gravity does not bend Space and Time if I am not mistaken…it is rather the shape of Space and Time and a little further if I can remember maybe, that Gravity is similar to the centrifical effect one would experience if Space Time were curved and that Einstein was perplexed at first in how the effects of Gravity were instantaneous so he deduced that it was instead of a force…merely the contour . I got sidetracked as a child and I hope I can recall enough to understand your topics. I have a Blog on WordPress. But my site is mostly Short Stories and Poetry. Thanks.

  22. misha permalink
    January 7, 2014 4:02 pm

    Dear Mr Lipton, Mr Regan,

    I am writing to express my gratitude that I owe to this blog. I have started to read it a couple of months ago and I aim at reading the entire blog from the very beginning.

    Best regards,

  23. April 11, 2015 11:07 am

    P = NP

  24. Stephen Gismondi permalink
    August 26, 2015 1:12 pm

    Just a thank you. I finally caught up on some reading (articles that you posted over the past several months) and I thoroughly enjoyed them. You and your group of contributors have a “knack” for writing a nice balance of theory, mixed with new ideas, rhetorical questions – and even humour. It’s all presented at a level that enables us to understand the main ideas. Just so you know – I think your work here is great!

  25. September 4, 2015 8:28 am

    I understand that there are many failed attempts to prove that P! = NP or its best part that P = NP, Most already forgotten which is the true purpose of the science and research, try, fail, try and fail, one day these things work, and someday, are everyday things.

    I would ask one chance, never again to bother, just ask an opportunity.

    P vs NP (A possible solution):
    An implementation in Plain and Pure Python:

    Thank you and sorry for the inconvenience.

  26. DPM permalink
    October 20, 2015 12:27 pm

    Dear Prof. R. J. Lipton,

    You may enjoy reading following:

    Best, DPM

    • August 18, 2016 3:31 am

      I am writing, first to express my appreciation of this blog – fascinating for one who did poorly at math in school and since has rediscovered it, largely through chaos theory and fractal programming. Still lots of catching up to do, but the drive is there.
      Second, to wonder about getting help in solving a problem associated with a find of mine. This is a family of “infinite sets of tiles of the regular reptiles in dimensions above 1” – at least, my explorations have all been in d=2, but I expect the find to hold in d=3 and up. 2 dimensions, however, offer quite enough richness that I have not even tried 3d yet… Some of my best finds, for the square and equilateral triangle which are the only regular reptiles in 2d, are at:
      Having not ventured past a side length of 6, and still with over 6000 examples programmed as either L-systems (Lindenmayer) or IFS (Iterated Function Systems) fractals, I would be interested to be proven wrong that the sets are infinite. But my real question is about the calculation formula of all possible such tiles for a given side length of a given reptile, including or excluding ones which are identical but can be calculated in different ways. It likely must involve numbers for side length, dimension and number of sides. If such a question in combinatorics interests you, I look forward with gratitude to a reply or any pointers in the right direction.
      Thanks much,
      Tony Hanmer
      Iskari, Upper Svaneti, Republic of Georgia

      • August 19, 2016 12:06 pm

        Thank you very much in return. Both of us were traveling each of the past two days, partly hence the delay. Once your first comment is modded in, most further ones are immediate.

  27. Ilyas permalink
    April 19, 2017 5:48 pm

    Hi there. Your book is both elegant and effective. I should have sent this messages ages ago. Along with Scott’s work, you and Ken have done a huge service to a whole generation of quantum theorists. Thank you.

    Ilyas Khan
    Cambridge Quantum Computing

  28. Samuel Kohn permalink
    August 24, 2017 7:22 pm

    Another errata for “Quantum Algorithms ….”

    On page 21, the sentence “Figure 3.1 exemplifies this for a graph called the four-cycle, C4” should come before the previous sentence “In that case, consider the matrix A’ =1/d A.”

    The way it reads now makes it sound like the four cycle is 1/d A.

    • Samuel Kohn permalink
      August 25, 2017 1:48 pm

      Another nitpick or critique – On page 22 you write A G (where G is sub-scripted). This is never defined as A(G) from page 20. Also the comment is not clear. Are you saying G is a d-regular graph or is G more general than this.

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