I'm currently reading about functional dependencies.I've read Armstrong's axioms about:    Relexivity: $if$ $B\subseteq A$ $then$ $A\to B$Augmentation: $if A\to B$ $then$ $AC\to BC$Transitivity: $if A\to B$ $and$ $B\to C$ $then$ $A\to C$   and also about:    Union Rule: $if A\to B$ $and$ $A\to C$ $then$ $A\to BC$Decomposition Rule: $if A\to BC$ $then$ $A\to B$ $and$ $A\to C$  I also know that for a relation R(A, B, C, D, E) that:$if A\to B$ $then$ $ACDE\to B$. In fact, the left side could be any superset of A.Is there a name for this rule?I've looked at various books but while they use it in examples, they never mention a name.
Functional Dependencies in Relations
database theory