1,452 reputation
319
bio website kmlinux.fjfi.cvut.cz/…
location Prague, Czech Republic
age 27
visits member for 2 years, 2 months
seen 21 hours ago

Math PhD student at Czech Technical University in Prague and at LIAFA in Paris. At the same time, I'm a typesetter (and partly the copy editor) of one scientific journal (done in LaTeX, of course).

Code licence details applicable on my posts on TeX.SX.

My favourite queries on SE's Data Explorer


Sep
30
awarded  Explainer
Sep
29
comment Is the perimeter of a nested convex set smaller than the containing set's?
@Martín-BlasPérezPinilla Damn, my fault. Sorry for that.
Sep
20
comment Proof my by mathematical induction $\sum_{i=1}^{n} \frac{(-1)^{i-1}}{i} > 0 $
Hello, is really your summand independent of $i$? Because currently the sum evaluates to $(-1)^{n-1}$, which is not always positive...
Sep
19
comment Are $10\times 10$ matrices spanned by powers of a single matrix?
+1 Indeed a very nice proof by contradiction.
Sep
19
answered If A is a matrix, what does A' mean?
Sep
5
comment Can an observed event in fact be of zero probability?
@Did however, the question was on iid $[0,1]$.
Sep
5
comment Can an observed event in fact be of zero probability?
@Aahz No, the fact that you observed it once doesn't mean you'll observe it again later.
Aug
31
comment Why induction cannot be used for infinite sets?
Hello! Could you please tell us where the problem comes from and what have you tried to solve it?
Aug
31
comment Does the string of prime numbers contain all natural numbers?
I love that you have two solutions here: you show that every $k$ is a prefix of a prime written in the decimal system, the other answer shows that every $k$ is a suffix of it :)
Aug
23
comment Make $n$ cents with $1$-cent, $2$-cent, and $3$-cent coins
Well, citing the question: Is there a way to do this without making use of a generation function?
Aug
23
comment Make $n$ cents with $1$-cent, $2$-cent, and $3$-cent coins
That still uses generating functions though, only simplifies the argument.
Aug
22
suggested rejected edit on If $A$ and $B$ are closed subsets of the set of real numbers, then is $A+B$ closed?
Aug
22
revised Make $n$ cents with $1$-cent, $2$-cent, and $3$-cent coins
improved MathJaX formatting
Aug
22
suggested approved edit on Make $n$ cents with $1$-cent, $2$-cent, and $3$-cent coins
Aug
22
answered Make $n$ cents with $1$-cent, $2$-cent, and $3$-cent coins
Aug
22
comment Make $n$ cents with $1$-cent, $2$-cent, and $3$-cent coins
@Ragnar That gives a generalized Tribonacci sequence, which is much more than $\sim n^3/12$.
Aug
22
comment Make $n$ cents with $1$-cent, $2$-cent, and $3$-cent coins
Well, then the answer can't be correct since even with only 1c and 2c coins, there are $f_n$ (Fibonacci number) solutions; that's exponential, not polynomial.
Aug
22
comment Make $n$ cents with $1$-cent, $2$-cent, and $3$-cent coins
Are $5=1+2+2=2+1+2=2+2+1$ three different solutions? It seems not, but I'm not sure
Aug
17
comment Is there an interval notation for complex numbers?
@Teepeemm It's not interval arithmetics, it's simply set arithmetics with addition and multiplication, and you can do this over any ring, right?
Aug
17
comment Is there an interval notation for complex numbers?
@JimmyK4542 It is common to define $X+Y = \{x+y:x\in X, y\in Y\}$ IMHO. There's no need to introduce an extra symbol for that.