Unwisdom's user avatar
Unwisdom's user avatar
Unwisdom's user avatar
Unwisdom
  • Member for 8 years, 8 months
  • Last seen more than 1 year ago
  • District of Columbia
52 votes
Accepted

Any natural number is greater than or equal to its product of digits.

23 votes
Accepted

Determine the number of equivalence relations on the set {1, 2, 3, 4}

19 votes
Accepted

Category Theory and Lebesgue Integration.

17 votes

Best way to express 2014

12 votes
Accepted

Is conditional probability also probability?

9 votes
Accepted

Some reference for categorical logic?

8 votes

Continuity of Extended Reals

8 votes
Accepted

Initial Segments and Initial Sections of Posets

7 votes

$\varnothing$ in the category of sets

7 votes
Accepted

Continuity of Fixed Point

5 votes
Accepted

An open cover $\{U_\alpha\}$ of $X$ is locally finite iff each $U\alpha$ intersects $U_\beta$ for only finitely many $\beta$

5 votes
Accepted

Help solving a challenge - relational algebra or second order logic

5 votes

Intuition/How to determine if onto or 1-1, given composition of g and f is identity. [GChart 3e P239 9.72]

5 votes

What was the first bit of mathematics that made you realize that math is beautiful? (For children's book)

5 votes

Chain Rule for more than two functions, general formula.

5 votes

Are all mathematical statements true or false?

4 votes
Accepted

Are orthogonal spaces exhaustive, i.e. is every vector in either the column space or its orthogonal complement?

4 votes

Sum of two periodic functions is periodic?

4 votes

A function such that $f(f(n)) = -n$?

3 votes

Elementary topology problem

3 votes
Accepted

How can infinity be an accumulation point?

3 votes
Accepted

Russel paradox doesn't occur at this instance?

3 votes

Does having a countable subbasis also satisfy the second axiom of countability?

3 votes
Accepted

Statistical Question for Probability for Choosing Cards

3 votes

If $g \circ f $ is injective, why must $f$ be injective but not $g$?

3 votes

Work and time problem . People leaving work one by one and at the same time reducing their rate of doing work.

3 votes
Accepted

$f$ is one-to-one with domain $\mathbb{R} - \{ a\} $ implies range $\mathbb{R} - \{ b\} $?

3 votes
Accepted

Conditions for convergences of a net

3 votes
Accepted

$f[A]\cap f[B]\supsetneq f[A\cap B]$ - Where does the string of equivalences fail ? [Chartrand 3E 9.12(b), 9.29]

3 votes

The Term Neighborhood in Mathematics

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