## Khovanov homology and related topics

Hello math community. Is there anybody here who is interested in Khovanov homology, categorification of skein modules, and things like this? I’m a PhD student starting to work in this area, and it would be great to talk to some other people about these topics.

submitted by Nevin Manimala Nevin Manimala /u/FreezeThatFrog

## Puzzled by seemingly inexplainable sequence

I came up with this idea/sequence/problem while having my hair cut the other day (don’t ask me why), and haven’t been able to explain the math behind it ever since. Here’s how it goes:

If one of your parents’ (let’s take your father as an example) age was a multiple of 9 when you were born, then your ages follow an interesting sequence. Let’s say I was born when my dad was 27.

Then, when my dad is 30, I am 03.

When my dad is 41, I am 14.

When my dad is 52, I am 25.

When my dad is 63, I am 36.

And so on.

It turns out that, for the case in which your parent’s age was a multiple of 9 when you were born, your ages are flipped numbers (25 <–> 52) every 11 years. Additionally, the sequence first starts when your age equals your parent’s age at the time when you were born, divided by 9. In the example above, the sequence starts when I am 27/9 = 3 years old.

Is it possible to derive the logic of this sequence analytically? Since there’s no simple math operator that flips numbers around (i.e. 36 <–> 63), it made me intrigued as to why/how this sequence is possible in the first place.

Let me know what your thoughts are!

submitted by Nevin Manimala Nevin Manimala /u/PaperPlane36

## Need help defining a particular system.

This is the only place where I can think to post this, so apologies in advanced.

I’m looking for a word to describe a system. It works like this.

X causes Y, X is removed, and Y continues to perpetrate Y.

Real world (very rough) example would be like alcoholism causes poverty, and poverty perpetrates poverty. Something like vicious cycle but not quite. Thanks!

submitted by Nevin Manimala Nevin Manimala /u/DiddledByDad

## Can someone please explain me what actually is coding theory?

Hello, I am 1st year engineering student. My team has chosen the topic ‘Application of Matrices in Coding Theory’. We have to give a presentation on it. It was my proposal because I found it really interesting and useful while reading the wiki and now I have the responsibility of making a presentation on it. I really want my audience to understand the topic and give a knowledge worthy presentation but before that I need to fully understand it.

What I know so far: Coding theory is a technique through which you code data or information efficiently for transmission and storing using different coding techniques.

For example: Using Invertible Matrices you can encode the message, encrypt is and then send it to the receiver where it can be decoded and decrypted using the formula, A-1(AB) = B where B is the encoded message

What I would like to know is this definition of coding theory correct? Where else there is a use of Matrices in Coding Theory?

submitted by Nevin Manimala Nevin Manimala /u/sr1jan

## I confess that I am a crappy math student and suffering from consequences. I need some advice.

Hello, there. I am a college student interested Pure Mathematics, and I am not sure if I should consider giving up on Pure Mathematics.

To be perfectly frank with people here, I have had a bad attitude all this time regarding what to do with mathematical assignments. I would try to do them, only to often find out that I struggle with solving/proving harder questions. I would go for TAs and teachers for help, and oftentimes they end up giving so much that they simply gave away the answers.

I faced the consequences now after getting a C/D in final grade in Complex Analysis. I have realized that I have never had that much of an experience with proving things by myself, so that finals/midterms became a lot harder for me.

I am thinking of doing Real Analysis and/or Groups and Rings next term, and I curious about two things:

1. Do I have any reason to give up now as my ability to prove things are blatantly weak?
2. Is there any advice anyone can give about preparing, practicing and doing assignments in order to improve myself?

I know many of you probably have received so many of these kind of posts in the first place, so I am sorry if this post came off as redundant.

submitted by Nevin Manimala Nevin Manimala /u/mathadvicethrow