# Matemáticos Chibchas

less info
reputation
1417
bio website location age member for 1 year, 3 months seen 56 mins ago profile views 770

A shy, neither amateur nor high-class, mathematician from Colombia.

 9 Compute $\sum_{j=1}^k\cos^n(j\pi/k)\sin(nj\pi/k)$ 8 Does this double series converge? 8 Does anyone know a closed-form expression for a bijection between $\mathbb{N}^k$ and $\mathbb{N}$? 8 How to prove “eigenvalues of polynomial of matrix $A$ = polynomial of eigenvalues of matrix $A$ ” 8 Interpolation of analytic function on unit disk

# 3,797 Reputation

 +10 Proof of $(\mathbb{Z}/m\mathbb{Z}) \otimes_\mathbb{Z} (\mathbb{Z} / n \mathbb{Z}) \cong \mathbb{Z}/ \gcd(m,n)\mathbb{Z}$ +10 Ideal generated by 3 and $1+\sqrt{-5}$ is not a principal ideal in the ring $\Bbb Z[\sqrt{-5}]$ +25 Prove that $(f(x)-x)^2 \not|f( f(…f(x)))) - x$ +10 Suppose that $G$ is a group with the property that for every choice of elements in $G$, $axb=cxd$ implies $ab=cd$. Prove that $G$ is Abelian.

# 22 Questions

 12 Explicit formula for Bernoulli numbers by using only the recurrence relation 12 2 questions about “$\mathbb R$ has a Hamel basis over $\mathbb Q$” 7 Obtaining binomial coefficients without “counting subsets” argument 6 Integral domain whose irreducible elements are not prime 6 Does $I^{-1}$ invertible imply $I$ invertible?

# 78 Tags

 44 real-analysis × 20 24 elementary-set-theory × 9 34 sequences-and-series × 14 19 complex-analysis × 7 32 abstract-algebra × 16 15 linear-algebra × 5 32 homework × 12 14 ring-theory × 7 26 analysis × 8 13 combinatorics × 9

# 8 Accounts

 Mathematics 3,797 rep 1417 Science Fiction & Fantasy 218 rep 6 Anime & Manga 136 rep 2 Mathematica 118 rep 4 Meta Stack Overflow 101 rep 1