Is Rg, calculated in the linked PDF calculating the pulldowm/pullup resistor for a MOSFET gate?
The lecture deals with DC steady state analysis of the MOSFET.  Pull-up and pull-down play the role when there is switching or transient behavior.

I wouldn't call RG1 and RG2 in the lecture pull-up and pull-down.  In the lecture, they form a resistor divider, which sets the gate voltage.  They may have as well drawn an ideal voltage source between gate and ground.