He is putting his money where his mouth is. In his Telmex fixed-line phone company in Mexico, where workers on a collective labour contract who joined the company in their late teens are eligible to retire before they are 50, he has instituted a voluntary scheme allowing such workers to keep working, on full pay, but for only four days a week.
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Mr Slim stunned the Mexican business world this month with plans to break up his América Móvil empire, selling about a fifth of its assets, in order to avoid regulatory sanctions. His companies dominate 80 per cent of the fixed-line and 70 per cent of the mobile markets in Mexico – above a new 50 per cent threshold.
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The magnate is a keen strategist and philanthropist, who has often said what he likes to do best is to think. He has cultivated interests outside the corporate world: his passion for Rodin sculpture and art collecting is evident in the Soumaya museum in Mexico City dedicated to his late wife.
Another of his deep-held beliefs is that education should be rethought. He told the conference in Paraguay that it should "not be boring, but should be fun" and should teach people "not to memorise but to reason; not to domesticate but to train". He also called for more vocational training.
Mr Slim, meanwhile, appears to have no plans to retire.
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"Look at who he respects: the [Mexican] banker Manuel Espinosa Yglesias was something of a mentor, and he was still working in his late 80s," said Andrew Paxman, a British historian who is writing a book about Mr Slim.
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