This section gives an overview of all relevant classes for extending MMT by additional type checking rules. The class relevant for checking judgments is checking.Solver. MMT uses the following judgments:
| Judgment | Description | 
|---|---|
G ctx | 
      G is a well-formed context | 
    
Inh T | 
      T is inhabitable (may occur on the right side of a typing judgment) | 
    
Univ T | 
      Tis a universe (inhabitable, and every t:T is also inhabitable) | 
    
t1 = t2 [:T] | 
      t1 is equal to t2 (under optional type T) | 
    
t1 ~> t2 | 
      t1 simplifies to t2 | 
    
t :=> T | 
      The principal type of t is T | 
    
t :<= T | 
      t checks against the given type T | 
    
T1 <: T2 | 
      T1 is a subtype of T2 | 
    
Prov T | 
      T is inhabited | 
    
In general, whenever a constant c : T [= d] is parsed, the solver will check the following judgments:
Inh Td :<= TThe classes corresponding to these judgements and the tactics used to check them are described here.