This claim states a fundamental property of asymmetrical relations and subset inclusion in formal logic, making it a matter of definition and everyday observation that requires no empirical citation.
The claim refers to basic propositional or set logic (if set A is a subset of set B, an element can belong to B without belonging to A; or similarly in material implication). This is a definitional truism of formal logic rather than an empirical hypothesis requiring literature support. Therefore, it satisfies the criteria for COMMON_KNOWLEDGE under Step 0.