The article discusses the Arrow-Debreu theory, which focuses on the existence and optimality of competitive equilibrium in economics. This theory has been developed through the contributions of many economists and mathematicians, with Arrow and Debreu being particularly influential. The main goal of the research is to elaborate on the Walras-Pareto theory of value and its implications for economic equilibrium. The key findings highlight the rigorous work done by Arrow and Debreu in shaping this theory, which has become a cornerstone in economic analysis.