--- a/src/HOL/Analysis/Gamma_Function.thy Fri Jul 05 21:59:43 2024 +0100
+++ b/src/HOL/Analysis/Gamma_Function.thy Sat Jul 06 12:51:31 2024 +0100
@@ -2756,7 +2756,7 @@
exp (z * of_real (\<Sum>k = 1..n. ln (1 + 1 / real_of_nat k)))"
by (subst exp_sum [symmetric]) (simp_all add: sum_distrib_left)
also have "(\<Sum>k=1..n. ln (1 + 1 / of_nat k) :: real) = ln (\<Prod>k=1..n. 1 + 1 / real_of_nat k)"
- by (subst ln_prod [symmetric]) (auto intro!: add_pos_nonneg)
+ by (subst ln_prod [symmetric]) (auto simp: divide_simps)
also have "(\<Prod>k=1..n. 1 + 1 / of_nat k :: real) = (\<Prod>k=1..n. (of_nat k + 1) / of_nat k)"
by (intro prod.cong) (simp_all add: field_split_simps)
also have "(\<Prod>k=1..n. (of_nat k + 1) / of_nat k :: real) = of_nat n + 1"