Update README.md

Signed-off-by: Fabiana 🚀  Campanari <113218619+FabianaCampanari@users.noreply.github.com>

Author: FabianaCampanari

README.md

@@ -1510,6 +1510,21 @@ Designate 4 workers to perform 4 tasks such that the total time to complete all
 
 <br>
 
+### [Mathematical Model]():
+
+### Decision Variables
+
+$$
+\[
+x_{ij} = 
+\begin{cases}
+1 & \text{if worker } i \text{ is assigned to task } j \\
+0 & \text{otherwise}
+\end{cases}
+\]
+$$
+
+### [Where](): $\( i, j \in \{1, 2, 3, 4\} \).