SWI-Prolog -- inf/2

Documentation
- Reference manual
  - The SWI-Prolog library
    - library(clpqr): Constraint Logic Programming over Rationals and Reals
      - Solver predicates
        
        {}/1
        
        entailed/1
        
        inf/2
        
        sup/2
        
        minimize/1
        
        maximize/1
        
        bb_inf/5
        
        bb_inf/4
        
        bb_inf/3
        
        dump/3
- Packages

inf(+Expression, -Inf)

Computes the infimum of Expression within the current state of the constraint store and returns that infimum in Inf. This predicate does not change the constraint store.