The article examines economic growth in Mexican states from 1940 to 2015, focusing on whether states are catching up to each other. They used a complex math model to analyze income gaps between states over time. They found that about 40% of states show a consistent pattern in their income gap changes. Only 6% to 15% of states are actually catching up to the national average. They identified 55 to 76 groups of states that are converging, with each group having 3 to 7 states. These groups overlap a lot, making it hard to interpret the overall pattern.