I am very excited to announce that our newest product TrueShelf.org is now available to everybody. TrueShelf.org is a BlockChain powered social learning platform. Users on the platform get rewarded with EulerCoin (the platform’s cryptocurrency) for creating and curating quality education content. The platform creates new tokens at a rate determined by mathematical rules that align the incentives between content creators, researchers, educators, teachers and students.
Go ahead and signup, post an article explaining some concept in mathematics or computer science / open problem / multiple-choice question / exercise. Content creators earn EulerCoin proportional to the number of likes (aka upvotes) of their content. More details of the token allocation and its game-theoretic analysis are coming soon in our white paper.
Here are some examples of user generated content from our beta version:
TrueShelf.org’s mission is to unleash the unlimited potential of such quality content creators, researchers, educators, teachers and students from all over world and make learning more engaging, efficient and effective.
At TrueShelf Inc, we now have two platforms:
If you want to know what motivated me to create TrueShelf (an AI powered adaptive learning platform) and the future of learning, please read my interview on Edsurge.
Wish you all a Very Happy New Year. Here is a list of my 10 favorite open problems for 2014. They belong to several research areas inside discrete mathematics and theoretical computer science. Some of them are baby steps towards resolving much bigger open problems. May this new year shed new light on these open problems.
- 2. Optimization : Improve the approximation factor for the undirected graphic TSP. The best known bound is 7/5 by Sebo and Vygen.
- 3. Algorithms : Prove that the tree-width of a planar graph can be computed in polynomial time (or) is NP-complete.
- 4. Fixed-parameter tractability : Treewidth and Pathwidth are known to be fixed-parameter tractable. Are directed treewidth/DAG-width/Kelly-width (generalizations of treewidth) and directed pathwidth (a generalization of pathwidth) fixed-parameter tractable ? This is a very important problem to understand the algorithmic and structural differences between undirected and directed width parameters.
- 5. Space complexity : Is Planar ST-connectvity in logspace ? This is perhaps the most natural special case of the NL vs L problem. Planar ST-connectivity is known to be in . Recently, Imai, Nakagawa, Pavan, Vinodchandran and Watanabe proved that it can be solved simultaneously in polynomial time and approximately O(√n) space.
- 6. Metric embedding : Is the minor-free embedding conjecture true for partial 3-trees (graphs of treewidth 3) ? Minor-free conjecture states that “every minor-free graph can be embedded in with constant distortion. The special case of planar graphs also seems very difficult. I think the special case of partial 3-trees is a very interesting baby step.
- 7. Structural graph theory : Characterize pfaffians of tree-width at most 3 (i.e., partial 3-trees). It is a long-standing open problem to give a nice characterization of pfaffians and design a polynomial time algorithm to decide if an input graph is a pfaffian. The special of partial 3-trees is an interesting baby step.
- 8. Structural graph theory : Prove that every minimal brick has at least four vertices of degree three. Bricks and braces are defined to better understand pfaffians. The characterization of pfaffian braces is known (more generally characterization of bipartite pfaffians is known). To understand pfaffians, it is important to understand the structure of bricks. Norine,Thomas proved that every minimal brick has at least three vertices of degree three and conjectured that every minimal brick has at least cn vertices of degree three.
- 9. Communication Complexity : Improve bounds for the log-rank conjecture. The best known bound is
- 10. Approximation algorithms : Improve the approximation factor for the uniform sparsest cut problem. The best known factor is .
Here are my conjectures for 2014 🙂
- Weak Conjecture : at least one of the above 10 problems will be resolved in 2014.
- Conjecture : at least five of the above 10 problems will be resolved in 2014.
- Strong Conjecture : All of the above 10 problems will be resolved in 2014.
Have fun !!
One year back (on 6/6/12) I announced a beta version of TrueShelf, a social-network for sharing exercises and puzzles especially in mathematics and computer science. After an year of testing and adding new features, now I can say that TrueShelf is out of beta.
TrueShelf turned out to be a very useful website. When students ask me for practice problems (or books) on a particular topic, I simply point them to trueshelf and tell them the tags related to that topic. When I am advising students on research projects, I first tell them to solve all related problems (in the first couple of weeks) to prepare them to read research papers.
Here are the features in TrueShelf 1.0.
- Post an exercise (or) multiple-choice question (or) video (or) notes.
- Solve any multiple-choice question directly on the website.
- Add topic and tags to any post
- Add source or level (high-school/undergraduate/graduate/research).
- Show text-books related to a post
- Show related posts for every post.
- View printable version (or) LaTex version of any post.
- Email / Tweet / share on facebook (or) Google+ any post directly from the post.
- Add any post to your Favorites
- Like (a.k.a upvote) any post.
Feel free to explore TrueShelf, contribute new exercises and let me know if you have any feedback (or) new features you want to see. You can also follow TrueShelf on facebook, twitter and google+. Here is a screenshot highlighting the important features.
Today (March 26 2013) is the 100th Birthday of Paul Erdos. The title of my Blog is inspired by one of his famous sayings “My Brain is Open”. In one of my earlier posts I mentioned a book titled “The Man Who Loved Only Numbers” about his biography.
Paul Erdos published more than 1500 papers. Most of them left a legacy of open problems and conjectures. What is your favorite open problem from Erdos’s papers ? Leave a comment. Hope we can solve some of his open problems during this special year.
Here are some interesting links :
If you know any interesting Erdos links, leave a comment.
Here is a painting of Paul Erdos, I made couple years back.
In my previous post (see here) I mentioned some interesting puzzle books. In today’s post I will mention different type of recreational math books i.e., biographical books. Here are my top three books in this category. They are must-read books for anybody even remotely interested in mathematics.
There are about three mathematics : (1) Andrew Wiles, whose determination to solve Fermat’s Last Theorem inspires future generations and gives a strong message that patience and focus are two of the most important assets that every mathematician should posses. (2) Paul Erdos, whose love for mathematics is so deep and prolific and (3) Srinivasa Ramanujan, whose story is different from any other mathematician ever.
1) Fermat’s Enigma: The Epic Quest to Solve the World’s Greatest Mathematical Problem
This is one of the first “recreational” books I read. It starts with the history of Fermat’s last theorem (FLT), discusses the life style of early mathematicians and moves on to talk about Andrew Wiles’s 8 year long journey proving FLT. Watch this BBC documentary for a quick overview of Andrew Wiles’s story.
2) The Man Who Loved Only Numbers: The Story of Paul Erdos and the Search for Mathematical Truth
Paul Erdos is one of the greatest and most prolific mathematicians ever. The title of my blog is inspired by one of his famous sayings “My Brain is Open”. I don’t want to reveal any details of this book. You will enjoy this book more if you read it without knowing anything about Paul Erdos. I should warn you that there are some really tempting open problems in this book. When I first read this book (during my PhD days) I spent almost one full semester reading papers related to Twin Prime Conjecture and other number-theoretic problems. I also wrote a paper titled “A generalization of Erdos’s proof of Bertrand-Chebyshev’s theorem”. Watch this documentary “N is a number” for a quick overview of Paul Erdos’s story.
3) The Man Who Knew Infinity: A Life of the Genius Ramanujan
This is a very dense book. I bought it five years back and only recently finished reading it. This books covers lots of “topics” : south indian life-style, Hardy’s life, Ramanujan’s proofs and his flawed proofs, his journey to work with Hardy, his health struggles etc. It is definitely worth-reading to know the details of Ramanujan’s passion for mathematics.
Most of us encounter math puzzles during high-school. If you are really obsessed with puzzles, actively searching and solving them, you will very soon run out of puzzles !! One day you will simply realize that you are not encountering any new puzzles. No more new puzzles. Poof. They are all gone. You feel like screaming “Give me a new puzzle“. This happened to me around the end of my undergrad days. During this phase of searching for puzzles, I encountered Graceful Tree Conjecture and realized that there are lots of long-standing open “puzzles”. I don’t scream anymore. Well… sometimes I do scream when my proofs collapse. But that’s a different kind of screaming.
Sometimes, I do try to create new puzzles. Most of the puzzles I create are either very trivial to solve (or) very hard and related to long-standing conjectures. Often it takes lots of effort and ingenuity to create a puzzle with right level of difficulty.
In today’s post, I want to point you to some of the basic puzzle books that everybody should read. So, the next time you see a kid screaming “Give me a new puzzle“, simply point him/her to these books. Hopefully they will stop screaming for sometime. If they comeback to you soon, point them to Graceful Tree Conjecture 🙂
1) Mathematical Puzzles: A Connoisseur’s Collection by Peter Winkler
2) Mathematical Mind-Benders by Peter Winkler
3) The Art of Mathematics: Coffee Time in Memphis by Bela Bollobás
4) Combinatorial Problems and Exercises by Laszlo Lovasz
5) Algorithmic Puzzles by Anany Levitin and Maria Levitin
I will mention more recreational math books in part 2 of this blog post.