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Karl Kronenfeld

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24
Why is $\;n^2-\frac{n^2}{2} =\frac{n^2}{2}\;$?
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20
What are two continuous maps from $S^1$ to $S^1$ which are not homotopic?
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14
Atiyah Macdonald – Exercise 2.15 (direct limit)
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13
injection $\mathbb{N}\times\mathbb{N}\to\mathbb{N}$
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12
Induction without a base case
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11
Difference between basis and subbasis in a topology?
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10
Is $(\ln 2)^2$ transcendental?
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9
On simple groups $G$, where $2\mid |G|$, $4\not\mid |G|$
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9
Prove that if for all $aba=bab$ then $|G|=1$.
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8
Is $(p \to q) \to r$ logically equivalent to $p \to (q \to r)$?
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8
Give an example of a UFD having a subring which is not a UFD.
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7
If $0<c<1$, then show $0<c^2<c<1$.
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7
The group $\mathbb{Q}^\times / \left( \mathbb{Q}^\times \right)^2$
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7
Seeking proper terminology
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6
A problem about localization of $\mathbb{Z}/6\mathbb{Z}$ at prime ideal $2\mathbb{Z}/6\mathbb{Z}$
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6
Example of quotient mapping that is not open
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6
how many sides does a dot have
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5
When do we have $A \subset B$ imples $f^{-1}(A) \subset f^{-1}(B)$?
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5
P(x) is x-special???
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5
Chopping arithmetic on terms such as $\pi^2$, $\pi^3$ or $e^3$
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5
Properties of Continuous Functions
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5
Cardinalities of generating sets for finite groups
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5
Legendre Symbol Sum?
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5
If $A$ is an $R$-module with some sort of ring structure, is it true that any $R$-submodule of $A$ is an ideal of $A$?
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5
Proof by contradiction concerning prime numbers. Where is the contradiction?
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