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Smithey's user avatar
Smithey's user avatar
Smithey
  • Member for 9 years, 2 months
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24 votes
7 answers
10k views

Strategy for reading math books, is it better to prove the theorems yourself or just read them?

6 votes
0 answers
624 views

Show constructively that the sequence definition of continuity implies the epsilon-delta definition

4 votes
0 answers
120 views

Do repeated roots (and Real Jordan form) for ODE's come up in real world applications of ODE's

3 votes
1 answer
633 views

Show that in the sequence space $l^1$, the unit ball with respect to $d_1$ is closed in the topology induced by the sup metric $d_\infty$

3 votes
1 answer
2k views

Show that a set that is open in the subspace topology is open in the full space topology.

3 votes
0 answers
53 views

Is there a name for this property of multiplication (and other functions)?

3 votes
0 answers
36 views

When is a matrix-valued function the Hessian of some (not nec. convex) function? [closed]

2 votes
0 answers
26 views

Separation by functional in a subspace of the dual space

2 votes
1 answer
48 views

Expected payoff based on two independent exponential distributions

2 votes
1 answer
268 views

Show that if $x$ is a limit point of a subset $A$ of a space $X$ which has a countable basis, then there is a sequence in $A$ converging to $x$

2 votes
0 answers
63 views

Show the set of mixed strategy - utility profiles such that each player is indifferent between all of her strategies is a manifold.

2 votes
1 answer
247 views

Show $S^2$ cannot have a smooth vector field with two zeros that are either both sources or both sinks

2 votes
1 answer
67 views

Change of speed problem (differential equations)

1 vote
1 answer
409 views

Showing $\operatorname{diag}(x)-xx'$ is positive definite on the tangent space of the unit simplex.

1 vote
1 answer
234 views

What's wrong with this alternative notion of Lebesgue inner measure: sup of sums of lengths of collections of closed intervals contained in the set?

1 vote
1 answer
468 views

Can the set of singletons with positive measure in a probability space be uncountable?

1 vote
1 answer
372 views

Show the cone on the integers is not locally compact

1 vote
0 answers
570 views

How to show $P^n$ (real projective space of dimension n)is triangulable?

1 vote
1 answer
126 views

Given three arbitrary points in the euclidean plane, is there a way to homeomorphic map the plane so that the points become colinear?

1 vote
0 answers
88 views

Explanation of Optimal Control Theory in terms of Frèchet derivatives

0 votes
0 answers
45 views

What is the linear functional associated with the dense subspace of polynomials in $\mathcal{C}[a,b]$?

0 votes
0 answers
74 views

Connections btw Fourier Transform, Probability characteristic functions, Cancelation, Concentration Inequalities, CLT

0 votes
1 answer
72 views

How to show duality of $l_1$ and $l_\infty$ balls using linear programming duality.

0 votes
1 answer
102 views

Integral of derivative of $f(t,t)$ wrt one argument only

0 votes
0 answers
24 views

Is there an analog of covariance matrix to three dimensional arrays?

0 votes
1 answer
34 views

Ref Request: Infinite Dimensional Lagrange Multipliers, KKT Conditions, and Control

0 votes
0 answers
22 views

Quasi-Concave Function $u(x,y)$ has Decreasing Marginal Rate of Substitution

0 votes
1 answer
139 views

If $X, Y$ are topological spaces, does $A \times B$ closed in $X \times Y$ imply $A$ closed in $X$ and $B$ closed in Y?

0 votes
1 answer
512 views

How to understand oriented intersection number in the non-transversal case? (including in the definition of Euler characteristic)

0 votes
1 answer
168 views

Solving Optimal Control Problem with Integral Constraint (Insurance Model Application)