Inflation may occur if there is "excessive demand with limited supply." This means that when there is an increase in demand for goods and services in the economy, but the supply of these goods and services is limited, their prices tend to rise.
For example, when consumers have more money to spend due to higher wages or government stimulus, they may demand more goods and services, which can lead to an increase in prices if the supply of those goods and services is not able to keep up with the demand.
Inflation is not caused by "excess supply over demand" because when there is more supply of goods and services than demand, prices tend to fall. An "increase in productivity" can actually lead to lower prices if it allows for the production of more goods and services at a lower cost. "Increased government spending in a depressed economy" can stimulate economic growth and create jobs, but it is not a direct cause of inflation unless it leads to an increase in demand for goods and services that exceeds the available supply.