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Charlie Parker's user avatar
Charlie Parker's user avatar
Charlie Parker's user avatar
Charlie Parker
  • Member for 10 years, 5 months
  • Last seen more than a month ago
38 votes
2 answers
40k views

Proof of when is $A=X^TX$ invertible?

32 votes
9 answers
9k views

Why is continuity characterized with open sets?

28 votes
7 answers
16k views

What does the decomposition, weak union and contraction rule mean for conditional probability and what are their proofs?

23 votes
6 answers
12k views

When to use the contrapositive to prove a statment

21 votes
3 answers
14k views

How do you compute numerically the Earth mover's distance (EMD)?

20 votes
3 answers
9k views

What is the intuition of why convergence in distribution does not imply convergence in probability

16 votes
1 answer
8k views

How do you prove $x^2$ is convex using only the definition of convexity?

15 votes
2 answers
7k views

Intuition on why the average minimizes the euclidean distance

15 votes
3 answers
2k views

Why does the fixed point theorem justify the existence of the factorial function?

15 votes
8 answers
3k views

Why doesn't the definition of dependence require that one can expresses each vector in terms of the others?

14 votes
5 answers
1k views

What is an intuitive way to understand the dot product in the context of matrix multiplication?

14 votes
8 answers
3k views

Why is the topological definition of continuous the way it is?

13 votes
2 answers
4k views

Intuition of multivariable chain rule

12 votes
5 answers
14k views

Why does raising group elements to the power of the order of the group yield the identity?

12 votes
7 answers
2k views

What is an intuitive explanation to why elimination retains solution to the original system of equations?

11 votes
3 answers
876 views

What is the precise mathematical definition of what a wavelet is and what is its relation to linear algebra?

10 votes
2 answers
7k views

Why is Euler's totient function equal to $(p-1)(q-1)$ when $N=pq$ and $p$ and $q$ are prime in a clean intuitive way?

10 votes
1 answer
18k views

How do you estimate the mean of a Poisson distribution from data?

10 votes
4 answers
1k views

Why does Rudin define $k = \frac{y^n-x}{n y^{n-1}}$ or $h < \frac{x - y^n}{n(y+1)^{n-1}}$ when he tries to prove that every real x has a nth root?

9 votes
6 answers
2k views

Why is complete strong induction a valid proof method and not need to explicitly proof the base cases?

9 votes
4 answers
6k views

Understanding conditional entropy intuitively $H[Y|X=x]$ vs $H[Y|X]$

8 votes
3 answers
2k views

What is the intuition behind the definition of the kernel of a homomorphism

8 votes
3 answers
22k views

How to express the Frobenius norm of a matrix as the squared norm of its singular values?

8 votes
5 answers
3k views

Why is the definition of stronger statement the way it is in logic?

7 votes
3 answers
13k views

How does one choose the step size for steepest descent?

7 votes
4 answers
1k views

In the category $\mathbf{Set}$ is "the product of an empty set of sets a one-element set"?

7 votes
2 answers
25k views

Proof that the Euclidean norm is indeed a norm

7 votes
3 answers
2k views

What is the proof that the rank of a matroid is sub-modular?

6 votes
2 answers
1k views

What is a mathematically rigorous justification for multiplying edge probabilities of a tree diagram

6 votes
1 answer
934 views

Intuitive explanation of why a chord of a convex function has to be a straight line

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