# What does capital letter I mean in this formulas?

Hello I don't understand meaning of the symbol represented by a capital letter "I" in the formulas below. There is a link to the paper with the formulas.

At the beginning I thought it mean "where c is not equal to the result of classifier T(m)", however in step (d) there is a multiplication symbol before it, so it probably mean that "I" should "return" a value.