# normal modal logic

> set of modal formulas containing all propositional tautologies and all instances of the Kripke schema ◻(A→B)→(◻A→◻B) and closed under modus ponens and necessitation

**Wikidata**: [Q840226](https://www.wikidata.org/wiki/Q840226)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Normal_modal_logic)  
**Source**: https://4ort.xyz/entity/normal-modal-logic


## References

1. Freebase Data Dumps. 2013
2. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)