6.1 Black-Scholes Equation: a Type of Backward Kolmogorov Equation6.2 Black-Scholes Equation: Risk-Neutral Pricing6.3 Black-Scholes Equation: Relation to Risk Premium Definition6.4 Black-Scholes Equation Applies to Currency Options: Hidden Symmetry 16.5 Black-Scholes Equation in Martingale Variables: Hidden Symmetry 26.6 Black-Scholes Equation With Stock as a “Derivative” of Option Price: Hidden Symmetry 3