Why does temperature change the friction coefficient of my stovetop? I have a Ceran cooking field at home, it's a glass-ceramic surface with heating coils embedded beneath. When I slide a pan around there's much more friction on a hot plate than on a cool one. Why?
Later clarification: My cooking field has regular thermal heating, it's not an induction oven.
The oven:

The pan, notice the concentric grooves:

The pan has clearly seen better days, maybe the organic residues do play a role, as John Rennie suggested.
 A: My guess is that it is hot gas or water vaper trapped between the pot / pan and the surface of the range.  That layer of gas separates the metal pan from the ceramic / glass range-top and makes it more lubricious.
A: user3533030's answer looks possible, but let me propose an alternative explanation. (I am not claiming this is the right answer!)
Heat may deform the pan, thus reducing the contact surface with the stove and the friction force.
Argument towards this explanation:
Pans are known to change shape with heat (thermal dilation). Some bad  pans even make a "clack" noise when dilation makes it necessary for the pan to suddently change its overall shape and take a shape far from a flat surface.
I think you could try some experiments to help determining the cause of the phenomenon:


*

*If you heat the stove first, and then put the cold pan on it, is the friction the same as if both where cold?

*Try to estimate friction between the stove and a clean wiping cloth with both the stove and cloth cold, and then hot. Unless there is some reconfiguration of the fibers of the cloth with heat, I think the contact surface should be the same, so if you see a difference in the friction between cold and hot, this would be in favor of some temperature-dependent behaviour of a thin coating on the stove such as residual oil.
