New answers tagged permutations
3
votes
Conceptual reason why the sign of a permutation is well-defined?
There is an interesting wrong "proof" by Hans Liebeck in the American Mathematical Monthly article Even and odd permutations: He claims that if a product of transpositions $(1\;i)$ is the ...
- 20.2k
1
vote
Accepted
Maximizing a sum minus its maximal summand
It is true. The proof rests on several observations.
The first one is that if you want to maximize $\sum_i i\pi_i$ under the condition $\pi_j\le B_i$ with any prescribed $B_i$, then your best bet is ...
- 58.2k
4
votes
Accepted
Left-shift cycle generating maps $f:\{0,1\}^{c_0}\to\{0,1\}$ for fixed length $c_0$
Such map cannot exist for $n=c_0+(2^{c_0})!$.
Assume the contrary. Write an infinite word by starting with any $c_0$ digits; then, at each step, if the last $c_0$ digits are $x_1,\dots,x_{c_0}$, ...
- 22k
Top 50 recent answers are included