Will find all Content Items which have the Layer "Corporate Information" assigned, but there is no English value for the Title available aka this syntax finds all Content Items with an empty Title in the Layer. 

-_exists_:fieldpath AND layerSchemaIds:LayerId
CODE
-_exists_:fieldpath AND layerSchemaIds:LayerId
CODE
-_exists_:corporateInformation.title.en AND layerSchemaIds:CorporateInformation
CODE