This is the 11097th most frequent Catalan word.
substitueixen
"Substitueixen" means "they substitute" or "they replace."
Here, 'substitueixen' is used to denote the act of replacing one set of rules with another.
Les noves regles substitueixen les antigues.
The new rules replace the old ones.
In this context, 'substitueixen' highlights the replacement of workers by robots in a workplace.
Els robots substitueixen alguns treballadors a la fàbrica.
Robots replace certain workers in the factory.
This usage illustrates substitution in the context of recipe ingredients.