Permutation

• Permutation is a kind of arrangement where all the elements are used ($n=p$)

Permutation Simple

• An arrangement where $n=p$

$$P_n = n!$$

Permutation with repetition

• $n$: available number of elements
• $a,b,c$: number of times each component repeats
• Use cases: anagrams of words with repeating letters

$$A^{a,b}_{n} = \frac{n!}{a!b!c!}$$

Permutation Circular

$$P^{circular}_n = (n-1)!$$