In an enhancement type MOSFET (an n channel one assumed here), when a positive gate to source voltage is applied, the holes of the substrate near the gate move deeper into the substrate away from the channel, and the electrons of the source and drain region accumulate near the gate to form the channel.
At the same time, the minority carriers of the substrate (electrons) should also be assisted by the electric field to accumulate in the channel region.
The book by Sedra and Smith mentions that only the source and drain electrons form the channel, while Boylestead's book states that the minority carriers of the substrate are involved in channel formation.
So, can I assume that both these mechanisms are involved in channel formation?