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PRIMES

Last edited: August 8, 2025

“very prime has a succinct certificate”

\begin{equation} \text{PRIMES} : \qty {A \mid A\text{ is prime}} \end{equation}

The certificate?

\begin{equation} A \text{ prime} \Leftrightarrow \exists 1 < b < A : B, B^{2}, \dots, B^{A*2} \not \cong \ \text{mod}\ A \end{equation}

So \(\text{PRIMES} \in \text{NP}\)


But actually PRIMES is in \(P\)

principle of induction

Last edited: August 8, 2025

The principle of induction is a technique used to prove the relationship between a smaller subset

The following three statements are equivalent.

standard induction

Suppose \(S \subset \mathbb{N}\), which is non-empty. If \(S\) is a non-empty subset such that \(0 \in S\), and for all \(n \in \mathbb{N}\), \(n \in S \implies n+1 \in S\). Then, \(S = \mathbb{N}\).

strong induction

Suppose \(S \subset \mathbb{N}\), which is non-empty. If \(S\) is a non-empty subset such that \(0 \in S\), and for all \(n \in \mathbb{N}\), \(\{0, \dots, n\} \in S \implies n+1 \in S\). Then, \(S = \mathbb{N}\).

printf

Last edited: August 8, 2025
printf("text %s\n", formatting, text, here);
  • %s (string)
  • %d (integer)
  • %f (double)

privacy

Last edited: August 8, 2025

“privacy as an individual right”

  • privacy is a control of information: controlling our private information shared with others
    • free choice with alternatives and informed understanding of what’s offered
    • control over personal data collection and aggregation
  • privacy as autonomy: your agency to decide for what’s valuable
    • autonomy over our own lives, and our ability to lead them
    • do you have agency?

“privacy as a social group”

  • privacy as social good: social life would be severely compromised without privacy
    • privacy allows social
  • privacy as a display of trust: privacy enables trusting relationships
    • “fiduciary”: proxy between you and a company
    • “should anyone who has access to personal info have a fiduciary responsibility?”

key trust questions

  • who/what do we trust?
  • what do we do if trust isn’t upheald?
  • how to approach building trust

trust

trust: to stop questioning the responsibility of something

probabilistic programming

Last edited: August 8, 2025

Remember Bayes Rule in Baysian Parameter Learning:

\begin{equation} P\qty(\theta | D) = \frac{P\qty(D | \theta) p \qty(\theta)}{\int_{\theta}P\qty(D | \theta) p \qty(\theta) \dd{\theta}} \end{equation}

we can’t actually easily compute the bottom without taking an analytic integral; instead we can sample from it.

If you want analytical form, you should hope that your likelihood function is a conjugate prior which allows us to analytically update prirors.