Intereting Posts

Simple(r) proof that $\pi(2^n)\geq n$?
What is an efficient nesting of mathematical theorems?
Why Not Define $0/0$ To Be $0$?
Euler's Approximation of pi.
Convolution of half-circle with inverse
If $\omega \in \Omega^q(M)$, and $(\omega|_{U})_p = 0$, is $\omega_p = 0$?
Let $G$ be a finite Abelian group and let $n \in \Bbb Z^+$ that is relatively prime to $|G|$. Show that $a \rightarrow a^n$ is automorphism.
Green's Theorem
$A\subseteq B\subseteq C$ ring extensions, $A\subseteq C$ finite/finitely-generated $\Rightarrow$ $A\subseteq B$ finite/finitely-generated?
Normal Operators: Polar Decomposition (Rudin)
Proving $\sum_{k=1}^n k k!=(n+1)!-1$
Inverse Limits: Isomorphism between Gal$(\mathbb{Q}(\cup_{n \geq 1}\mu_n)/\mathbb{Q})$ and $\varprojlim (\mathbb{Z}/n\mathbb{Z})^\times$
Understanding the ideal $IJ$ in $R$
How to calculate the coordinates of orthocentre.!!
A nontrivial p-group has nontrivial center

2 aliens walk on a line randomly. At each timestep they walk independently either left or right (1 meter) with equal probability. They start 10 meters apart. What’s the probability that after 7 time steps they have met(Passed though the same point)?

Hello,

I’m trying to solve this puzzle but I’m struggling. I know that there are $4^7$ states in the tree. If we imagine them being on a number line. Alien A starting at $0$ and Alien B starting at $10$. I know that they can only meet at points 3-7.

- Do men or women have more brothers?
- Maximal inequality for a sequence of partial sums of independent random variables
- Exercise regarding Poisson processes and the uniform distribution
- Show $\lim_{n \to \infty} \sum_{i=1}^n Y_i/\sum_{i=1}^n Y_i^2 = 1$ for Bernoulli distributed random variables $Y_i$
- Binomial probability with summation
- In how many ways can 20 identical balls be distributed into 4 distinct boxes subject?

I know that the probability of Alien A getting to 3 after 3 time steps is $\frac{1}{8}$.

I don’t really know where to go from here. Thank you for your suggestions.

- Expected value of two successive heads or tails (stuck on computation)
- Average bus waiting time
- Ratio between highest number among $n$ and $n+1$ samples
- How to prove Boole’s inequality
- PDF of a sum of exponential random variables
- Summing (0,1) uniform random variables up to 1
- Probability that two random numbers are coprime
- What is the intuition behind the Poisson distribution's function?
- Exploding (a.k.a open-ended) dice pool
- Expected Value of sum of distinct random integers

- Book suggestion geometry of Banach spaces
- Matrix graph and irreducibility
- Laplacian as a Fredholm operator
- Can the semidirect product of two groups be abelian group?
- If $n,k\in\mathbb N$, solve $3^k-1=x^n$.
- TVS: Topology vs. Scalar Product
- The limit of infinite product $\prod_{k=1}^{\infty}(1-\frac{1}{2^k})$ is not 0?
- Help on solving an apparently simple differential equation
- Enumerations of the rationals with summable gaps $(q_i-q_{i-1})^2$
- An intuitive approach to the Jordan Normal form.
- Prove that $10101\ldots01$ can't be a perfect square.
- Integral of Schwartz function over probability measure
- $\mathbb{C}/(f,g)$ is an artinian ring, if $\gcd(f,g)=1$.
- Proof by Induction for inequality, $\sum_{k=1}^nk^{-2}\lt2-(1/n)$
- Countable set of truth assignments satisfying set of well formed formulas