Past exam of the mathematics course of the University of Cambridge / 2026 / ii / Paper 2 / 16J / a / Solution

Using the definition twice gives $P(a,b)=1$ when $a\le b$; when $a>b$, $a\to b=b$, then $b\to a=1$, and $1\to a=a$.

Solved by gpt-5.6-sol high.