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High GPA
  • Member for 6 years, 11 months
  • Last seen more than a month ago
40 votes
2 answers
2k views

From $e^n$ to $e^x$

11 votes
3 answers
625 views

The continuity of $g\circ h$ and $h$, and $h$ surjective, imply the continuity of $g$?

10 votes
3 answers
2k views

What is the gentlest notes/book of intro differential topology? [closed]

8 votes
3 answers
377 views

What are some strategies to write a proof that can be easily comprehended?

7 votes
3 answers
2k views

Is the number of dimensions in Hilbert Space countable infinity or uncountable infinity?

7 votes
1 answer
213 views

$\frac{(x-y)^3}{x+y}\neq g(f(x)-f(y))$?

6 votes
2 answers
212 views

Simple functional equation: $f(x)=f(y) \implies f(ax)=f(ay)$

5 votes
1 answer
419 views

Learning to translate natural-language phrases to formal logic

5 votes
1 answer
316 views

Can the derivative difference be arbitrarily larger than the function difference?

5 votes
2 answers
380 views

Prove that a construction exists: is this a constructive proof or existential proof?

5 votes
2 answers
545 views

Solve equation $x^{1/4}=-1$

4 votes
2 answers
227 views

Solve FDE: $f^{(1.5)}(x)=f(x)$

4 votes
1 answer
522 views

Prove $2^e$ is transcendental

4 votes
1 answer
2k views

Can a function be neither convex nor concave everywhere?

4 votes
0 answers
78 views

Function $f$ intersects with any line at most twice

4 votes
1 answer
154 views

Either locally convex or concave?

4 votes
1 answer
639 views

Equivalence condition of Absolute Continuity

4 votes
2 answers
343 views

Suppose $f(x)-f(y)=h(g(x)-g(y))$, then $h$ is linear?

4 votes
1 answer
151 views

Increasing function $f(x,y,y)=f(x,x,y)$ implies $f(x,y,z)=g(x,z)$?

4 votes
1 answer
179 views

Solve continuous function: $f(bx)-f(by)=f(x)-f(y)$

4 votes
1 answer
68 views

$f$ is a real function. What is the largest interval $S$ such that no open subset $I\subset S$ makes $f(I)$ constant?

3 votes
1 answer
85 views

Can "plus" be order preserving as "times": does there exist a function $h$ such that $x\times y=x' \times y'\iff x+h(y)=x'+h(y')$?

3 votes
1 answer
220 views

Axioms for vector space and affine space under the same system and notation

3 votes
1 answer
2k views

Taking expectation with respect to a probability measure

3 votes
1 answer
205 views

Solve $\frac{f'(x)f'''(x)}{(f''(x))^2}=C$

3 votes
3 answers
576 views

A monotonic function that intersect with all lines in $\mathbb R^2$

3 votes
2 answers
221 views

What is the name of the complement of a nowhere dense set?

3 votes
1 answer
3k views

Is the integration of Lipschitz function still Lipschitz?

3 votes
1 answer
128 views

Functional and Borel measure

3 votes
6 answers
6k views

Is the whole set $\mathbb R$ open?

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