What happens when a Pope travels to Lebanon? A math problem

You know how sometimes a road gets repaired just before a VIP is going to visit?

Nadim Kobeissi, a computer science researcher at the American University of Beirut, used this to his country’s advantage. Sort of. In a research paper, he calculated the minimum number of times the Pope would have to visit Lebanon for all the country’s roads to be fixed.

After Pope Leo XIV announced a visit to Lebanon in 2025, roads and potholes that had been neglected for years were reportedly repaired in days.

Prof. Kobeissi imagined a system in which the Pope secretly chooses a random set of roads he might use during a visit. So the government knows some roads may be used but doesn’t know which, forcing the authorities to repair many roads to avoid embarrassment.

Using a mathematical formula, he estimated how quickly the total number of damaged roads would drop if the process repeated over multiple visits. Based on his assumptions, he estimated about 30% of broken roads would be repaired after each visit.

Using estimates for Lebanon’s road conditions and the government’s likely responsiveness, his model concluded that the Pope would have to visit around 12 times to bring the number of damaged roads to under 1% of the national network.

The work, uploaded to the internet as a preprint paper, is satirical. Still, it uses mathematical concepts in a clever way and also comments on how governments sometimes respond faster to international attention than to everyday public needs.