code: public String getComponent(Variable v) {
  		for (String s : components.keySet()) {
  			if (components.get(s).contains(v)) return s;
  		}
  		return null;
  	}
docs: Get the component of a given {@link Variable}.  A component is a {@link String} labeling of {@link Variable}s.
  @param v The {@link Variable} of which to get the component.
  @return A {@link String} representing the component of the given {@link Variable}.