# What’s on my wall?

Not gonna lie – I didn’t go to many open days before uni. I’d seen uni accommodation on various summer schools, and was aware that most uni rooms have a pinboard. I definitely didn’t expect one quite as big as the one in my room at Whitefields. I wasn’t really sure what I was going to use it for at first, but over the past few months, it’s come in pretty handy…

**1. A framed photo of my friends from sixth form**

New friends are silver, old friends are gold – when you make new friends, don’t forget the old. I forget who taught me that little rhyme when I was in junior school, but it’s really resonated with me at Warwick. Don’t get me wrong – the friends I’ve made in the past few months are great, but it’s pretty normal to miss friends from back home. I keep in contact with them over Facebook, and we share our weird little stories about our uni experiences.

**2. Definitions of injective and surjective functions**

I get these two muddled a lot, so I drew some pictures to remind me before my January exam. They’re big enough that I can read them anywhere in my room, so I’ll get them drummed into my head eventually.

For those who are interested, a function is something that maps every element of set A to an element in set B – i.e. it must be defined for all elements of A. So for example:

f: R -> R, f(x) = x^2 is a function because all real values of x have a real-value square. Meanwhile, g: R -> R, g(x) = sqrt(x) is not a function, because R includes negative numbers, which don’t have real square roots.

An injective function is a function where every element of B is mapped to by at most one element of A.

A surjective function is a function where every element of B is mapped to by at least one element of A.

(Also, if a function is both injective and surjective, it’s called bijective – every element in B is mapped to by exactly one element in A)

**3. Campus map**

Warwick has a pretty big campus, so it’s easy to get lost in the first few weeks of term! There’s an online interactive map that’s quite useful for finding rooms, but I like having my paper copy on the wall too.

**4. Euclidean Algorithm**

This is a method of finding the highest common factor of two numbers, and I learnt about it for my Foundations module. According to a friend who does compsci, it’s apparently useful in security.

**5. Definition of Completeness**

A more fancy revision poster – it took a lot longer than the others, but it was worth it because it came in handy in my January exam!

It says that “every non-empty set bounded above has a supremum” – a non-empty set contains at least one element. Being bounded above means that you can pick values that are bigger than all elements in the set (for example, the set {…, -2, -1, 0, 1, 2} is bounded above, because if I picked any number greater than or equal to two, all of the elements in the set are smaller than or equal to it). A supremum is the smallest number that you can pick that is greater than or equal to all elements in a set. Put all that together, and you’ve got a definition for completeness.

**6. Definition of continuity**

This one’s from Analysis II – I made sure to kick off the term by memorising the definition in poster form. It can be read as “for all epsilon greater than zero, there exists a delta greater than zero such that if x is in the set E and the difference between x and c is less than delta, then the difference between the function of x and the function of c is less than epsilon”.

**7. Pictures of different kinds of intervals**

These are closed and open intervals, denoted by different kinds of brackets. It’s a less long-winded way of writing things like a =< x =< b.

**8. Souvenirs from FIRST Lego League**

I got given some copies of the medals from the tournaments I helped at in December. Having done FLL since 2011, I’ve got quite a collection now!

**9. Wall calendar**

With the use of Google Calendar and such, it’s not really an essential, but I jot notes down occasionally.

**10. Timetable**

My timetable changes a lot (picking up/dropping options, fitting in society stuff, etc), so I find it easier to look at a paper copy than a digital one.

**11. Warwick Quiz Society Flyer**

I got given this at the Societies Fair, and have kept it since then. Quiz Society is a big part of my "when I’m not maths-ing" Warwick experience.

**12. Greek Alphabet**

One of my flatmates is learning Greek as part of his course, so he wrote out the Greek alphabet for me. As a maths student, I’ve been seeing these letters a lot lately…

**13. Ticket to The Marriage of Figaro**

I went to see Opera Warwick’s adaptation at the Arts Centre with Quiz Soc, and it was very good!

**14. My flatmate’s opinions on breakfast foods**

It once came up in conversation as to what breakfasts are like “back home” in a mostly international flat. One of my flatmates wrote out the pieces of what she considers a Chinese breakfast and gave the list to me.

**15. More pins!**

I’ll probably need them.