Lean's type checker verifies all 5 theorems:
1. exp(x) = eml(x, 1)
2. e = eml(1, 1)
3. ln(x) = eml(1, eml(eml(1,x), 1))
4. 0 = eml(1, eml(eml(1,1), 1))
5. a - b = eml(ln(a), exp(b))
Zero sorry. Machine-verified. This is a proof, not numerical analysis.
