/- Copyright 2025 The Formal Conjectures Authors. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at https://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -/ module public import Mathlib.Combinatorics.SimpleGraph.Diam public import Mathlib.Combinatorics.SimpleGraph.Metric@[expose] public sectionassert_not_exists Fieldnamespace SimpleGraphvariable {α : Type*} {G G' : SimpleGraph α}

The diameter is the greatest distance between any two vertices. If the graph is disconnected, this will be 0.

lemma diam_eq_zero_of_subsingleton [Subsingleton α] : G.diam = 0 := α:Type u_1G:SimpleGraph αinst✝:Subsingleton αG.diam = 0 All goals completed! 🐙proof_wanted diam_ne_zero [Nontrivial α] : G.diam 0lemma nontrivial_of_diam_ne_zero' (h : G.diam 0) : Nontrivial α := α:Type u_1G:SimpleGraph αh:G.diam 0Nontrivial α α:Type u_1G:SimpleGraph αh:Subsingleton αG.diam = 0 All goals completed! 🐙section Pathopen Pathproof_wanted dist_le_diam_of_mem_path {G : SimpleGraph α} {u v : α} (p : G.Walk u v) (w : α) (hw : w p.support) : G.dist w u G.diamend Pathend SimpleGraph