Mgccl's Blog

I have decided to create a taxonomy database library based on direct acyclic graph(DAG). Like the tree taxonomy, except allow one node to have more than one direct parent node.
Like this structure, that can't be constructed from tree based taxonomy.

A hash table storing nodes. Indices are integers.
The node stores three sets of integers, the indices of direct parent nodes, the indices of direct child nodes, and the items.
The items are integers only, each item refers to the item wish to be classified. Those items can be thought as ids. When the database return items, those items can be used in a SQL query to request the content of items.

These are specs of the database, and all the possible operations:

1. Return all items directly under a node.
2. Return all items under a node or it's child nodes.
3. Return relationship from node A to node B.(parent, child or neither)
4. Return all items under a complex query. For example, items that are classified as part of node A but not node B
5. Insertion of new node
6. deletion of nodes
7. Find the smallest graph that contains some specific nodes as it's child node. Useful when there are things having the same name but different meaning. So with this process, it can return stuff like Graph(Graph Theory) and Graph(Plotting Functions)
8. Move a node from one place to another.(supply old parent and new parents, or supply a entirely new node)
9. Save/Load the database to/from a file
10. Normalization process of the database:
    1. If an node has an direct item that is also an direct item of any of it's child node. Remove the item from node.
    2. If an node has a direct parent node P1 and P2, if P1 is a child node of P2, then remove P2 from the direct parent node
    3. If an node has a direct child node C1 and C2, if C1 is a parent node of C2, then remove C2 from the direct parent node
    4. If nodes refer to nodes that doesn't exist, remove that reference
    5. Each time, insertion, alter, and deletion of nodes and items are operated, normalization operation starts, so the database is always normalized

In the end the database looks like this:

There will be a separated database handling converting integers ids into it's respectable names.

Slowly progressing. I only need to finish it by the time I start building a math problem database. C++ is hard.

In L: Change the WorLd, there was a geometry problem reveal some very important information and lead to the entire world's safety.
The problem itself isn't a big deal, it's just the message hidden in the answer of the problem. So here it goes.

The problem:

I believe the Japanese just means "Find it".
The solution:

So guess I got pwned by a 10 years old.

A proof of Riemann hypothesis by Xian-Jin Li was posted on arxiv.
I believe it is quite possible he proved the Reimann hypothesis. Even though is possible he made a mistake somewhere in the paper.
Xian-Jin Li is a real mathematician who stated Li's criterion.
Let's see how this goes, can't wait.
At the same time, screw those Chinese dudes create mathematical propaganda in the Chinese community. For example, Chun-Xuan Jiang[蒋春暄] and his evil math papers(look at the ones about Fermat or Reimann). This person, along with countless other math noobs goes around many Chinese forums and post complete rubbish in very professional style, most of these noobs claim to "Prove/Disprove Reimann hypothesis and Fermat's last theorem in less than 10 lines" or show that "There is no such thing as the smallest positive integer". Jiang even get on a TV show and telling people no one can say he is wrong because he is in such a high math level, no one understand what he is doing. Now I have completely lost all my respect for any Chinese media. China should concentrate their resources on stopping these kind of crap before censorship, because more and more people actually believe crap like this, Jiang have published his own book(That's what he claimed). They are killing the future of China! I think Martin Huxley's reply to Jiang said it best.

but anyway...
I only cared about 5 problem in mathematics when I was a young age
Fermat's last theorem [Tackled]
Reimann hypothesis [Come on, Li, make the world proud]
Integer factorization in polynomial time [If there is a quantum computer]
Goldbach's conjecture
P versus NP

It I hope I can live to see all of those problem solved.

Update: Terence Tao said there is an error in the proof.