All problems

E548:Erdős Problem #548 “Does every graph on n vertices with more than (k-1)n/2 edges contain every tree on k+1 vertices?”

Announcement of the FrontierMath Erdős results; names problem 548 among the five solved (proved) by GPT-6 Astra

Contributors

Verification

Verdict report: artifact 2f8e7735

CI run: GitHub Actions log

Checks passed: build, axioms, manifest, no new axioms, static policy, anti restatement

Axioms: Classical.choice, Quot.sound, propext

Toolchain: Lean v4.33.0, Mathlib db584cd (Jig's pins)

Solution

import Mathlib

/-!
# Attribution and verification scope

The mathematical proof and the entire proof body below were produced by GPT-6 Astra
in Epoch AI's FrontierMath Erdős experiments and publicly released by Epoch AI
(Lean 4.27, checked by SafeVerify). This file ports that existing proof to Jig's
pinned toolchain (Lean 4.33.0, Mathlib db584cd) and states the canonical
Erdős 548 proposition in the `Submissions.Erdos548ErdosSosTree.EpochPort` namespace.
It claims no new solution to Erdős problem 548: this is a kernel re-verification.

Port changes (four, all mechanical): `nsmul_eq_mul` → `smul_eq_mul` in one
cardinality count; `SimpleGraph.symm`/`loopless` now take `Std.Symm`/`Std.Irrefl`
structures; `isBridge_iff` is now stated directly as non-reachability in the
edge-deleted graph; `IsTree.IsAcyclic` → `IsTree.isAcyclic`.
EpochPort.lean
StatementUserModelHarnessTime
Prior art
1)V3For n at least k+1, every simple graph on n vertices with at least (k-1)n/2+1 edges contains every tree on k+…
@davidtsong
Fable 5.1
Claude Code
9/6/26