Proof of `Treewidth and Δ-forestwidth` (2nd statement)
groundedproofs/Lax461425Proofs/TreewidthForestwidth.lean · lax-461425
What this proof establishes
no assumptions
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
Description
Joining every node to its parent gives a tree (connected, with one edge per non-root node), and the nodes whose bags contain a vertex are connected to its unique top node.