diff --git a/20_Simulation_Principles/50_Multi-Model_Representation/10_Physics_integration.md b/20_Simulation_Principles/50_Multi-Model_Representation/10_Physics_integration.md
index 4f5c6f9a1..2285dc9e1 100644
--- a/20_Simulation_Principles/50_Multi-Model_Representation/10_Physics_integration.md
+++ b/20_Simulation_Principles/50_Multi-Model_Representation/10_Physics_integration.md
@@ -94,7 +94,7 @@ The shape functions $\phi$ can be expressed with regard to local coordinates $(\
 
 
 
-Therefore, it always exists a transformation $T^$ which can be defined as:
+Therefore, it always exists a transformation $T^K$ which can be defined as:
 
 $$
 T^K:\hat{K} \longrightarrow K