Simon Nickerson
• United Kingdom
• Member for 11 years, 2 months

 38 A challenge by R. P. Feynman: give counter-intuitive theorems that can be translated into everyday language 25 Division by imaginary number 19 Construct a bijection from $\mathbb{R}$ to $\mathbb{R}\setminus S$, where $S$ is countable 16 Are there any functions that are (always) continuous yet not differentiable? Or vice-versa? 16 How come $32.5 = 31.5$? (The "Missing Square" puzzle.)

### Reputation (5,221)

 +170 How can you prove that a function has no closed form integral? +10 Algorithm for calculating $A^n$ with as few multiplications as possible +10 Construct a bijection from $\mathbb{R}$ to $\mathbb{R}\setminus S$, where $S$ is countable +10 Number of finite simple groups of given order is at most $2$ - is a classification-free proof possible?

### Questions (5)

 333 How can you prove that a function has no closed form integral? 31 How do you prove that a group specified by a presentation is infinite? 22 Is there a real number lookup algorithm or service? 21 Algorithm for calculating $A^n$ with as few multiplications as possible 20 Number of finite simple groups of given order is at most $2$ - is a classification-free proof possible?

### Tags (28)

 25 algebra-precalculus 16 fake-proofs 19 elementary-set-theory 16 continuity 16 real-analysis × 2 0 soft-question × 3 16 recreational-mathematics 0 big-list × 2 16 geometry 0 group-theory × 2

### Bookmarks (7)

 167 Why do people use "it is easy to prove"? 110 Are there real world applications of finite group theory? 80 Logic problem: Identifying poisoned wines out of a sample, minimizing test subjects with constraints 71 How was the Monster's existence originally suspected? 32 Mandelbrot-like sets for functions other than $f(z)=z^2+c$?