# Bijection between Prüfer Sequences and Labeled Trees

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## Theorem

There is a one-to-one correspondence between Prüfer sequences and labeled trees.

That is, every labeled tree has a unique Prüfer sequence that defines it, and every Prüfer sequence defines just one labeled tree.

## Proof

Let $T$ be the set of all labeled trees of order $n$.

Let $P$ be the set of all Prüfer sequence of length $n-2$.

Let $\phi: T \to P$ be the mapping that maps each tree to its Prüfer sequence.

- From Prüfer Sequence from Labeled Tree, $\phi$ is clearly well-defined, as every element of $T$ maps uniquely to an element of $P$.

- However, from Labeled Tree from Prüfer Sequence, $\phi^{-1}: P \to T$ is also clearly well-defined, as every element of $P$ maps to a unique element of $T$.

Hence the result.

$\blacksquare$