Skip to content
Counterexample

Is this true?

Every UFD is a PID

No — it is false.

The counterexample

The object that kills this claim comes with Trap Analysis.

See pricing

86 counterexamples are free — including most of the ones Part C leans on hardest.

Keep practicing

Finite-dimensional intuition

Something true in ℝⁿ, or in a nice space, assumed in general.

Go deeper· Explained in full in The ring hierarchy and where each inclusion is strict· Asked in CSIR NET December 2024· From Rings and Fields › Euclidean, PID, UFD hierarchy

ShareWhatsAppTelegram