Is lac operon an example of positive control mechanism or negative control mechanism or both?

Lac operon is both types
According to CAP-CAMP pathway the Lac operon is positive control
And according the Repressor inhibition model the Lac operon behaves as an negative operon.
Positive control: If some thing (CAP/C-AMP) binds and becomes the factor for inhibition then it is negative control.
Negative Control: If some thing inhibitory (Repressor) compound is withdrawn from the operon then it is negative.
Go through the diagram belwo for more information.

Approved