Other mistake: When Nash is put into the car and is being taken away to the hospital, there is a line of people watching him drive away. Two of the spectators are the imaginary roommate and the little girl. They are standing in front of rest of the spectators. As the car is driving away you see a female student look around the imaginary roommate to see the moving car. If the roommate can only be seen by Nash why did she need to look around the roommate to watch the car drive away? (01:08:30)
Other mistake: In the end, when Nash gets standing ovations from the Nobel-prize audience, you can clearly see that the name Nobel is spelled wrong on the platform which he stands behind. (02:07:10)
Other mistake: When Nash receives his Nobel price, you can see the words "Stockholm, Sweden" at the bottom of the screen but in the French version the words are "Stockholm, Suisse" that means "Stockholm, Switzerland," as "Suisse" is the French word for Switzerland.
Answer: You do not specify to which scene you are referring. The only window I recall with writing on it would be the window in Nash's room. John had covered this window in mathematical equations, theorems and geometric patterns. While most of the symbols used are Greek in origin, the language is simply that of mathematics.
Michael Albert