Deleting edge from tree gives 2 trees

Dependencies:

  1. Tree
  2. Bridge in graph
  3. Deleting bridge from graph gives 2 components

Let $T = (V, E)$ be a tree. Suppose the edge $(u, v)$ is deleted from $T$ to get $T'$. Then $T'$ contains 2 connected components which are trees.

Proof

Since $T$ is a tree, there is a unique simple path between $u$ and $v$, which is $(u, v)$. Therefore, deleting $(u, v)$ will disconnect $u$ and $v$. This means $(u, v)$ is a bridge.

Since deleting a bridge gives 2 connected components, $T'$ contains 2 connected components.

Since $T$ is a tree, it is acyclic. Since removing an edge cannot create a cycle, $T'$ is also acyclic. Since each component in $T'$ is connected and acyclic, the connected components are trees.

Dependency for:

  1. |E| = |V| - 1 in trees
  2. Edge replacement in spanning forest using a cut

Info:

Transitive dependencies:

  1. /sets-and-relations/equivalence-classes
  2. /sets-and-relations/relation-composition-is-associative
  3. /sets-and-relations/equivalence-relation
  4. Graph
  5. Path in Graph
  6. Tree
  7. Bridge in graph
  8. Deleting bridge from graph gives 2 components