The economy is composed of the production of two conceptually distinct, mutually-definitive types of goods.  Depending on the context they may be named

• basic goods or surplus goods,
• consumer goods or producer goods,
• accelerated goods or accelerator goods,
• point-to-point goods or point-to-line goods.

An expansion of the surplus production function causes a later acceleration of the basic production function.  First one surge, then later the other surge.  Note the symbols for time (t) and (t-a) in the following formula, “the lagged technical accelerator.” (continue reading)

k_n[f’_n(t-a)-B_n] = f”_n-1(t) – A_{n-1        CWL 15, p. 37}