1. Semi-periodic waves: The term "semi-periodic wave" isn't a standard term in physics or signal processing. Periodic waves repeat their pattern exactly at regular intervals. A "semi-periodic" wave might refer to a wave that exhibits some periodicity, but with variations in amplitude, frequency, or waveform shape over time. It's not a precise definition, and its meaning would depend on the specific context in which it's used. It could describe a wave that has a dominant periodic component but with superimposed noise or irregular fluctuations. To understand what a specific author means by "semi-periodic waves," you'd need to examine the surrounding text and the context of their work. In contrast, a long wave usually refers to a wave with a very long wavelength (the distance between successive crests). This is a common term in various fields, including economics (Kondratiev waves), oceanography (tsunamis), and seismology (earthquakes). The length of the wave is the key distinguishing feature, not its periodicity. A long wave can be periodic, aperiodic, or semi-periodic as defined above. 2. Marx's Historicist Approach to Capitalism: Marx's approach to capitalism is considered historicist because he viewed capitalism not as a static or eternal system but as a specific historical stage of economic development. His key distinctions were: - Capitalism as a Stage: Marx saw capitalism as one stage in a larger historical process, ultimately destined to be replaced by socialism and then communism. This contrasts with non-historicist views that may see capitalism as a natural or permanent form of economic organization.- Material Conditions: He emphasized the importance of material conditions—the means of production, technology, and class relations—in shaping historical change. The development of capitalism, according to Marx, was driven by internal contradictions stemming from these material conditions.- Internal Contradictions: Marx argued that capitalism contained inherent contradictions that would eventually lead to its downfall. These contradictions include the exploitation of labor, the tendency for the rate of profit to fall, and the cyclical nature of economic crises. These internal dynamics, rooted in the material conditions, are central to his historicist perspective.- Class Struggle: The class struggle between the bourgeoisie (owners of capital) and the proletariat (workers) is a key driver of historical change within the capitalist system. This struggle, arising from the material conditions of capitalism, would ultimately lead to the revolution and the transition to a new social order. In essence, Marx's historicism emphasizes the dynamic and evolving nature of capitalism, its internal contradictions, and its eventual supersession by a different economic and social system. He didn't see capitalism as a fixed or timeless system but as a historical phenomenon with a beginning, a middle, and, according to his theory, an end.