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### Questions (94)

 11 Examples of Baire class 2 functions 9 The fastest trajectory that a particle should follow through two different mediums 8 Covariant derivative of a vector field along a curve 6 How to find the center of mass of half a torus? 5 Understanding the proof of $|ST||S\cap T| = |S||T|$ where $S, T$ are subgroups of a finite group

### Reputation (2,117)

 +10 Computing $H_q(S^{n-1} \cup_f D^n)$ with $f:S^{n-1} \to S^{n-1}$ +20 Finding all covering spaces of the orbit space $Z$ of an action $\Bbb Z_2 \times S^m \times S^n \to S^m \times S^n$ +10 Finding all connected covering spaces of the circle $S^1$ +10 Is $\pi_n(\Pi_\alpha X_\alpha) \approx \Pi_\alpha \pi_n(X_\alpha)$ if the $X_\alpha$ aren't path connected?

 126 Surprising identities / equations 7 Bijection between open and closed interval 4 A problem on Vector space over $\mathbb{C}$ and $\mathbb{R}$ 3 subsequences examples 2 $\lim_{n\to\infty}a = \lim_{n\to\infty}b$ implies $a=b$

### Tags (54)

 17 real-analysis × 20 3 proof-verification × 3 7 cardinals 3 elementary-set-theory × 2 5 calculus × 14 2 general-topology × 13 5 functions × 6 2 group-theory × 7 4 linear-algebra × 16 2 cauchy-sequences

### Accounts (4)

 Mathematics 2,117 rep 11 gold badge1313 silver badges3333 bronze badges TeX - LaTeX 191 rep 66 bronze badges Mathematica 101 rep Physics 101 rep