The term demand-pull inflation is mostly associated with Keynesian economics.
According to Keynesian theory, the more firms will employ people, the more people are employed, and the higher aggregate demand will become. This greater demand will make firms employ more people in order to output more. Due to capacity constraints, this increase in output will eventually become so small that the price of the good will rise. At first, unemployment will go down, shifting AD1 to AD2, which increases Y by (Y2 - Y1). This increase in demand means more workers are needed, and then AD will be shifted from AD2 to AD3, but this time much less is produced than in the previous shift, but the price level has risen from P2 to P3, a much higher increase in price than in the previous shift. This increase in price is called inflation