Is Cobb Douglas production function is constant elasticity substitution production function?

Yes, the Cobb-Douglas production function is a specific type of constant elasticity of substitution (CES) production function. In a Cobb-Douglas function, the elasticity of substitution between inputs is constant and equal to one. This means that the percentage change in the ratio of inputs used will result in a proportional percentage change in the marginal rate of technical substitution, reflecting a consistent trade-off between the inputs.