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2
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0answers
94 views

Good starting point for learning noncommutative geometry?

Currently, I am attempting to learn noncommutative geometry. My interests mostly lie on the boundaries of pure mathematics and theoretical physics, so I am not only interested in the mathematical ...
5
votes
3answers
144 views

Real Analysis book with pictures and ideas of proofs

I am taking real analysis course in my graduate class of Maths. My classes will start in 3 months. I have studied real analysis but not very rigorously. Whenever I see theorem I have no idea on how ...
0
votes
2answers
66 views

Looking for good intro book on differential equations

I am looking for a good book to study ordinary differential equations. My background is that I have successfully completed calculus 1 through 3. So this included derivatives and integrals, ...
0
votes
1answer
37 views

How to evaluate a squared sum?

I need (the name of) the formula to evaluate $(x_1 + x_2 + ... + x_n ) ^2$ . I know the question is not very interesting, but I am stuck and WolframAlpha also doesn't get my input. Thanks in advance
2
votes
2answers
101 views

Why are quadrants defined the way they are?

I was thinking about planes and things, and suddenly wondered why quadrants are defined the way they are, the first on the top-right, and so on. I wonder if this gives us any benefit, or if any ...
50
votes
3answers
1k views

What is this pattern called?

Back-Story I became interested in the patterns in multiplication tables for different base number systems a while ago. Specifically, the pattern made by the last digit of each number in the ...
9
votes
10answers
386 views

Is a pattern proof?

Let's say I want a formula that takes any number and makes it into 170, and I come up with a formula that I think does it. If I plug 1 into it, 2 into it, 3 into it, etc. up to a pretty large number ...
3
votes
1answer
71 views

Textbook +reference book in complex analysis

Which book can be used as an introductory textbook in complex analysis? I have some choices (more suggestions are welcomed) Marsden & Hoffman J.B. Conway Ahlfors Palka Lang Stein & ...
6
votes
1answer
152 views

Where is Cauchy's wrong proof?

Allegedly, Cauchy mistakingly "proved" that pointwise convergence of continuous functions is continuous. I saw this somewhere in a book, and it is also in wikipedia: Uniform convergence. In his ...
0
votes
1answer
61 views

Which discrete mathematics book do you think is better between Epp's and Rosen's for a clueless self-learner?

I am a programmer, and I want to become a machine learning researcher and a good software engineer. I dabbled with calculus, linear algebra, and real analysis for a few months when I was enrolled in a ...
1
vote
0answers
38 views

Referencing a Theorem in a Paper?

I'm making the final edits for a paper and I have a question more about the etiquette. I want to use a theorem from another paper and its obvious I have to cite it, but do I need to prove it too? I ...
1
vote
0answers
36 views

What are some genuine ways to define the derivative of a fractal?

Seeing the success of applying measure theory to generalize integration to fractals, I wonder whether or not there is a method to generalize the derivative to a fractal. Most courses start off fractal ...
2
votes
0answers
55 views

What is the point of basis vectors?

Why do we even bother with basis vectors? Why don't we just notate an element $x$ of an $n$-dimensional vector space $V$ as an ordered set $(x_1,x_2,...,x_n)$ and go from there?
8
votes
2answers
98 views

How would you explain a quadratic field to a beginner?

How would you explain a quadratic field to a beginner? Eg. how did the subject first start? All the modern stuff they use to explain it makes it really confusing how one should think about it in more ...
2
votes
1answer
67 views

Blow-up toric varieties.

I have to take a talk of an hour and I have to talk about blow-up of toric varieties. Can you suggest me some interesting examples that I can present? How can I find a good reference for the theory ...
3
votes
0answers
34 views

Generalizing convexity of sets

Let $X$ be a subset of some Euclidean space. We say that $X$ is convex if for any two points $p$, $q$ in $X$, the line segment joining $p$ and $q$ is also in $X$. But what if we loosen this definition ...
3
votes
0answers
40 views

What is the densest, most opaque way of saying two odd numbers add up to an even number? [closed]

Here's what I've come up with: In $\mathbb Z$, any pairwise sum of elements in the $\langle 2 \rangle + 1$ coset is in $\langle 2 \rangle$. But there's got to be a way to make this even briefer, ...
0
votes
3answers
38 views

Proving limits via episilon-delta definition vs. algebraic manipulation.

In real analysis textbooks, limits are proved using the epsilon-delta definition directly. However, at some point, limits start being solved using algebraic manipulation. For example: $$\lim_{x \to ...
2
votes
1answer
108 views

Amazing integrals and how is solved it [closed]

There a lot of integrals, however many people solved it in different ways, we can find interesting integrals in Table of Integrals, Series, and Products. I wonder What is the most exciting integral ...
1
vote
2answers
40 views

SDE Modeling: Ito vs. Stratonovich

In my SDE class last semester there were some hints that sometimes an SDE model makes more sense in the Ito sense, and sometimes in the Stratonovich sense. This was explained very briefly and vaguely. ...
0
votes
2answers
22 views

Given the solution to some differential equation, is the original equation necessarily unique?

For example, if I have the fundamental solution set $\{x^2\}$, such that $y(x)=Cx^2$ is the solution to some unknown differential equation, is it guaranteed that only one such equation exists with ...
1
vote
2answers
25 views

Confusion about division in rates.

I would really appreciate help with this because it's been driving me insane for a while now... I understand what "per" means in "$x$ kilometers per $y$ hours". What I don't understand is how to make ...
6
votes
1answer
93 views

Could the real numbers have been invented without the natural numbers

The real numbers are constructed from the rational numbers which are constructed from the integers which, in turn, are constructed from the natural numbers. But if we had no notion of the natural ...
2
votes
3answers
151 views

What is it like to understand complicated/advanced mathematics?

Whenever I see very complex equations, they look, in a way, beautiful even though I don't understand them. This was directly taken from another question: "- Definition 1 - Given an open subset ...
1
vote
0answers
65 views

Does Fractional Calculus have a real connection with Fractals? (or is it just an extra variable trick)

The fractional derivative and integral (operators that let you differentiate or integrate a fractional number of times) have drawn a lot of attention from people outside the field. Yet, after reading ...
0
votes
0answers
42 views

intuition about calculating partial sums of series

The partial sums $$1 + 2 + 3 + \cdots + n$$ of the simple arithmetic progression can be calculated by reordering and adding. The partial sums $$1 + \frac{1}{2} + \frac{1}{4} + \cdots + ...
0
votes
0answers
20 views

Stochastic integral and usual integral addition

Let's say I have two processes and I would like to say something about their sum. In the case of deterministic functions, $\int f(t)dt + \int g(t)dt = \int f(t)+g(t)dt $, and I can then possibly say ...
10
votes
0answers
138 views

Is it a good approach to heavily depend on visualization to learn math?

I am a third year undergraduate and I am a beginner on these "real mathematics" (no pun intended). Before contacting the "real math", my math level should be considered to be "good", although I was ...
5
votes
3answers
55 views

Odd and Even Parity in Proofs

The notion of the parity is very important in a variety of branches of mathematics. Specifically, I am looking for proofs that use parity in the even-vs-odd sense to prove their points. For example, ...
1
vote
0answers
32 views

Seeking after notation for two objects equal up to a constant

Sometimes we want to express that two objects are equal up to a constant but there is no need to keep writing out the constant or constants. For example, often times the constant or constants involved ...
6
votes
2answers
85 views

Exploring $ \sum_{n=0}^\infty \frac{n^p}{n!} = B_pe$, particularly $p = 2$.

I was exploring the fact that $$ \sum_{n=0}^\infty \frac{n^p}{n!} = B_pe,$$ where $B_n$ is the $n$th Bell number. I found this result by exploring the series on wolframalpha and looking up the ...
0
votes
0answers
32 views

What should I study, if I want to learn about higher dimensional spaces and objects? Also, what resources should I obtain?

I am becoming interesting in learning about higher dimensions. What are subjects I could study, and what are some good resources for those subjects?
34
votes
2answers
351 views

When are two proofs “the same”?

Often, we find different proofs for certain theorems that, on the surface, seem to be very different but actually use the same fundamental ideas. For example, the topological proof of the infinitude ...
2
votes
2answers
86 views

How to generate complicated looking identities such as $\sqrt [3] {2 + \sqrt 5} - \sqrt [3] {2 - \sqrt 5}=1$ easily?

How to generate complicated looking identities, or even more complicated looking identies such as $\sqrt [3] {2 + \sqrt 5} - \sqrt [3] {2 - \sqrt 5}=1$ easily? I saw the identity to be shown. What is ...
7
votes
2answers
270 views

An intuitive definition of contour integration.

Recently I have been trying to learn the method of contour integration, but the Wikipedia article and others don't really help. Is there some resource which provides a definition which can be followed ...
1
vote
0answers
19 views

Application of theorems 'about free groups'

What consequences have theorem Any nonzero subgroup of free group is free or some another similar theorems? P.S. especially not-group-theretic applications.
2
votes
0answers
81 views

Argument for the zero vector not being defined as an eigenvector

Two days ago, my lecturer of Advanced Numerical Methods gave a review on the topic about eigenvalues and eigenvectors. Just as the lecturer presented the definition of eigenvalues and eigenvectors, a ...
1
vote
0answers
36 views

Intuition for Entropy over Fractals

Is there intuition for "mathematical" entropy. I know that physical entropy tracks the order in a dynamical system, for thermodynamics. As entropy goes up, general randomness and disorder goes up. ...
1
vote
1answer
69 views

Understanding and teaching the concept of derivative

I need to prepare an introductory lecture about derivatives and the concept of differentiation to a class of people with a general mathematical background (who have also studied calculus a few years ...
0
votes
0answers
24 views

On the hypothesis of the change of variable theorem

I´m studying the change of variable theorem for a function $f:\mathbb R^n \to \mathbb R$ and my teacher gave us the theorem as follows: Theorem: Let $f:A\subset \mathbb R^n \to \mathbb R$ be ...
1
vote
1answer
55 views

informal semantics regarding CH and AC

why is the assertion $\aleph_1=2^{\aleph_0}$ referred to as a hypothesis, whereas $$\forall \alpha( S_\alpha \ne \varnothing) \Rightarrow \prod_\alpha S_\alpha \ne \varnothing$$ is called an axiom? ...
1
vote
1answer
41 views

how to understand Taylor's inequality intuitively?

I am learning the Taylor Series at the moment and I am trying to figure out how to understand Taylor's inequality intuitively. I know you can integrate repeatedly and prove the inequality is ...
3
votes
0answers
80 views

How to understand if one is eligible for research?

What are the eligibility criteria for one to undergo research in Mathematics? Or should I place the question as what virtues of a student are given importance when one is interviewed for a PhD ...
1
vote
5answers
145 views

Why do counits go that way?

Imagine you want to motivate for an audience the definition of an adjunction in terms of unit and counit. So you can say: Often two functors $\mathcal{C} \begin{array}{c} \stackrel{\large ...
1
vote
0answers
48 views

Surreal numbers in set theories other than ZFC

This isn't really a question rather than my thoughts on these things; I initially had questions but believe I managed to answer them. Regardless, here goes. Feel free to correct any mistakes, as I'm a ...
1
vote
1answer
83 views

How is problem solving ability on an olympiad level relevant to mathematical graduate study/research?

I am starting on math later than many of my peers and hence have little to no experience in competitive problem solving. Is this a disadvantage during the study of the more abstract mathematics that ...
0
votes
0answers
17 views

I hear that some operators don't have analytical properties. What does that mean?

The floor, ceiling, and mod functions are very useful operators, but in general discussion I've heard their usefulness called into question because of their lack of analytical properties. For instance ...
1
vote
1answer
95 views

Building a training program… for mathematics

I want to ask for your advice building my one-year training program for mathematics. Objectives: Keep 'mathematically fit' Improve for the pleasure Get competent at high-level economics and ...
1
vote
1answer
23 views

Expressing a line as a linear combination of two points on the line.

I'm currently reading Pugh's Analysis. He makes the statement that the line between two points x and y is the set of linear combinations $sx + ty$ where $s + t = 1$. I'm satisfied that this is true, ...
4
votes
3answers
116 views

Difficulty faced in solving maths problems

I am a student in 12th grade and am fond of mathematics. I enjoy reading mathematics but when it comes to problems I just get completely stuck. Its not that I don't understand the problem but often ...