Reconciling concurrency with unambiguity

Develop a concurrency model for Djinnlang that supports temporal properties and reconciles concurrent execution with the language’s unambiguity constraint.

Background

Djinnlang currently excludes concurrency: it is not thread-safe, has no shared mutable state, and provides no interleaving. The paper notes that specifying concurrent behavior requires temporal properties of the kind supported by TLA+, while the language’s central unambiguity constraint requires each executable specification to determine a unique output behavior.

The unresolved problem is therefore to design a principled concurrency extension for Djinnlang that can express temporal properties and account for interleavings without undermining the deterministic semantic guarantees required by unambiguous specifications.

References

Specifying concurrency needs temporal properties, as implemented in TLA+, and reconciling those with unambiguity is an open problem.

— Djinnlang: Higher-Level Programming by Unambiguous Specification with an LLM in the Compiler  (2609.23954 - Henniger et al., 21 Sep 2026) in Section 7, Limitations, paragraph “Concurrency”