##  [Backdoor Set Size](/backdoor-set-size) 

  ##  [Backdoor Set Size](https://mathlogic.quantumdictionary.io/backdoor-set-size-0) 

  

 [![Mathematics & Logic Dictionary](/sites/default/files/styles/large/public/2026-01/Mathematics%20%26%20Logic.png.webp?itok=UhtTRPnp)](/topic-specific-dictionaries/natural-formal-sciences/mathematics-logic)

- Natural & Formal Sciences -

**Mathematics & Logic Dictionary**

 







 

 

 

 



 

 

 

 

Definition

The minimal cardinality of a set of propositional variables such that some assignment to those variables reduces the instance to a member of a specified tractable fragment (e.g., Horn, 2-SAT).