Build the tree, one edge at a time

Start at A. Choose the lowest-weight edge with exactly one endpoint in the current tree. The numbers are weights; the drawing's lengths do not represent cost.

Focus S={A} · V∖S={B, C, D, E}
Chosen edges: ∅ · Total: 0 · 0/4

Thick solid edges: chosen. Dashed edges: unchosen. Node ∈S: in the current tree.

Shows the next edge and why it is allowed. It will not select the edge for you.

This checks your next edge selection. It does not grade a written proof.