
1) Mathematical logic 
Found on 
https://www.crosswordclues.com/clue/metalogic

 Metalogic is the study of the metatheory of logic. Whereas logic studies how logical systems can be used to construct valid and sound arguments, metalogic studies the properties of logical systems. Logic concerns the truths that may be derived using a logical system; metalogic concerns the truths that may be derived about the languages and systems...
Found on 
http://en.wikipedia.org/wiki/Metalogic

the study and analysis of the semantics (relations between expressions and meanings) and syntax (relations among expressions) of formal languages and ... [2 related articles]
Found on 
http://www.britannica.com/eb/a-z/m/78
  No exact match found.