user avatar
user avatar
user avatar
J.C.VegaO
  • Member for 2 years, 11 months
  • Last seen this week
4 votes
2 answers
126 views

number of real roots of $p(x) +p'(x)$

3 votes
1 answer
65 views

Is $E=\{(x,y) \in \mathbb R^2 | y^2-xy-x^3=0\}$ compact?

3 votes
2 answers
712 views

What are the operations in quaternions as a division ring?

3 votes
1 answer
39 views

if $A^X$ is a field, A being a ring, what can be concluded about $A$: field/ unital ring/ division ring?

3 votes
1 answer
118 views

Proving ${\mathbb{P}}^n$ is Hausdorff

3 votes
1 answer
46 views

Each chart of the canonical structure of a submanifold S is locally a submanifold chart

3 votes
1 answer
94 views

Making sense of the proof : The set $\{s_n(x)=(2/\pi)^{1/2} \sin nx:n \in \mathbb{N} \}$ is an orthonormal basis in $L^2[0,\pi]$- Rynne- Youngson

2 votes
0 answers
60 views

Is it enough to find $g$ not in $C([a,b])$ such that $f_{n}\rightarrow g$ in $||\cdot||_{p}$to conclude $(C[a,b],\|\cdot\|_p)$is not complete?

2 votes
1 answer
29 views

What is a sufficient condition for the singular values of a square matrix to be the modulus of its eigenvalues?

2 votes
2 answers
50 views

How to use Cauchy-Schwarz inequality to show the scalar product $\langle\xi,\eta\rangle=\sum_{i=1}^{\infty}\omega_i\xi_i\bar\eta_i$ is well-defined

2 votes
0 answers
76 views

How do I deal with the integration limits of the integrals that show up when showing that$Kx(t)=\int_0^tK(t,\tau)x(\tau)d\tau, x\in X$ is compact?

2 votes
1 answer
38 views

How do I prove $F_*Z=(Z^i\circ F^{-1})\partial_i'$, where Z is a field, and $(F(U),x\circ F^{-1})$ a chart with coordinate fields $\partial_i'$?

2 votes
1 answer
272 views

Why is a topological manifold defined with a countable basis?

2 votes
1 answer
41 views

example for $\varphi(H \cap K) \subset \varphi(H)\cap \varphi(K)$, $H, K< G$ and $\varphi \in Hom(G,G')$

2 votes
0 answers
41 views

Definition of homeomorphism is missing continuity of $f$ in metric spaces

2 votes
3 answers
137 views

Clarifying why compactness in a topology, implies compactness in a coarser topology

2 votes
1 answer
83 views

$I_n \sim I_m $ iff $ n=m $ by induction over n

2 votes
1 answer
72 views

Prove $\left<H\cup K\right>=H\lor K$

2 votes
5 answers
198 views

Train stops at $n$ stations

2 votes
1 answer
752 views

image of a dense set via a continuous surjective function is dense

2 votes
1 answer
92 views

How do I prove there is a homeomorphism between these two topological spaces?

2 votes
0 answers
96 views

what is this function called in english?

1 vote
1 answer
52 views

Prove $f(x,y) = |x-y|(x-y)$ is a function of class $C^1$

1 vote
2 answers
469 views

Equation of parabola in x-y plane

1 vote
1 answer
273 views

Relationship between moment of inertia of a solid with respect to a point and moments of inertia with respect to the axes

1 vote
2 answers
221 views

Does Lagrange Multipliers method provide a way to classify relative minimum and maximum points?

1 vote
1 answer
39 views

IS $(\mathbb{Z}_4,+) \rightarrow (\mathbb{Z}_5^{*},\cdot), n\pmod 4 \mapsto 2^n \pmod 5 $ well-defined??

1 vote
0 answers
74 views

Prove that $\mathbb{Z}_m$ and $\mathbb{Z}_n$ have the same cardinality iff m=n

1 vote
1 answer
68 views

How do I prove this topological space is T2 and compact?

1 vote
1 answer
50 views

What is wrong with my solution about the completeness of this metric space?

1
2 3 4 5