LOS 58b - equity forward contracts discounted, comparing, regarding, question, forward

troymo

Hi there,
I’m wondering about the formula in Schweser book 5 page 19 on the bottom regarding forwards on equity indexes.
Why is the index spot St discounted (and also: why is the index spot discounted by the div yield only). Same question for the future price FP: why by RFR and why discounted?? Somehow I don’t get the rationale for this calculation when comparing to the way to calculate the forwards on single equities.
Thx
Tom