Black Thursday
Last edited: August 8, 2025Black-Scholes Formula
Last edited: August 8, 2025People have been trading options for a very long time, but there wasn’t a good way of quantify the value of an option.
There are two main types of uses for Black-Scholes Formula
- you can use all variables and determine the value of options
- you can get the price of options being traded, then compute the $σ$—the market’s estimation of volatility (how much they want the insurance policy that is the options)
constituents
- \(S_0\): stock price
- \(X\): exercise price
- \(r\): risk-free interest rate
- \(T\): maturity time
- \(\sigma\): standard-deviation of log returns—“volatility”
Black-Scholes Formula for an European “Call” Option
Here is the scary formula:
BLB
Last edited: August 8, 2025blind lower bound
Last edited: August 8, 2025To evaluate the lower bound:
\begin{equation} \alpha_{a}^{k+1} (s) = R(s,a) + \gamma \sum_{s’}^{} T(s’|s,a) \alpha_{a}^{k}(s’) \end{equation}
we are essentially sticking with an action and do conditional plan evaluation of a policy that do one action into the future
bloch sphere
Last edited: August 8, 2025The bloch sphere is a sphere encoding all possible probabilities of a qubit shared between two axis, \(|u\big>\) and \(|d\big>\).

You will notice that its a unit sphere, in which any magnitude has size \(1\). Hence, probabilities would result as projected onto each of the directions.
