Relations	Sign	equation
X and Y are independent, if $$F_{X,Y}=0$$	(x,y)	(equation 19.1)
Instantaneous causality only without direction, if $$F_{X,Y}\ne 0,F_{Y\to X}=0,F_{X\to Y}=0$$	(x–y)	(equation 19.2)
X causes Y, with instantaneous causality, if $$F_{X,Y}\ne 0,F_{Y\to X}=0,F_{X\to Y}\ne 0$$	(x→y)	(equation 19.3)
X causes Y, without instantaneous causality, if $$F_{X,Y}=0,F_{Y\to X}=0,F_{X\to Y}\ne 0$$	(x=>y)	(equation 19.4)
Y causes X, with instantaneous causality, if $$F_{X,Y}\ne 0,F_{Y\to X}\ne 0,F_{X\to Y}=0$$	(x←y)	(equation 19.5)
Y causes X, without instantaneous causality, if $$F_{X,Y}=0,F_{Y\to X}\ne 0,F_{X\to Y}=0$$	(x<=y)	(equation 19.6)
Feedback with instantaneous causality, if $$F_{X,Y}\ne 0,F_{Y\to X}\ne 0,F_{X\to Y}\ne 0$$	(x↔y)	(equation 19.7)
Feedback without instantaneous causality $$F_{X,Y}=0,F_{Y\to X}\ne 0,F_{X\to Y}\ne 0$$	(x⇔y)	(equation 19.8)