# The Hunt for a Red Spider: Conjunctive Query Determinacy Is Undecidable

arXiv: https://arxiv.org/abs/1501.01817 · HTML: https://mlsanity.com/paper/1501.01817/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 8 Jan 2015.

## Built on by (most cited first, 1 of 1)

- [Identifiability of Relational Queries in Multi-View Pretraining](https://mlsanity.com/paper/2607.04735/) (2026)

## Abstract (arXiv)

We solve a well known, long-standing open problem in relational databases theory, showing that the conjunctive query determinacy problem (in its "unrestricted" version) is undecidable.