# 1_event set notation

I do not understand the notation as given here:

The source for the image is page 17 in this paper after equation 18.

I understand the first subset notation but what does 1_\e_t mean?

• It's the indicator random variable. – Neil G May 4 '17 at 6:02
• What is the meaning of an indicator random variable for a sigma field? – Adepu Ravi Sankar May 4 '17 at 6:05
• A random variable that takes on value 1 when the event happens, and 0 when it doesn't. So, if one event is a subset of the other, its indicator is less than the other's. – Neil G May 4 '17 at 6:25
• Picture not showing for me! – SmallChess May 4 '17 at 7:33
• Pl click this i.stack.imgur.com/dSPUR.png – Adepu Ravi Sankar May 4 '17 at 10:11