diff -r 32e95d996acc -r ef9f95d055f6 src/HOL/Tools/ATP/atp_problem_generate.ML
--- a/src/HOL/Tools/ATP/atp_problem_generate.ML	Thu Nov 11 12:02:08 2021 +0100
+++ b/src/HOL/Tools/ATP/atp_problem_generate.ML	Thu Nov 11 15:34:02 2021 +0100
@@ -1270,7 +1270,7 @@
         let val argc = length args in
           if has_ite andalso s = "c_If" andalso argc >= 3 then
             IConst (`I tptp_ite, T, [])
-          else if is_fool andalso s = "c_Let" andalso argc = 2 then
+          else if is_fool andalso s = "c_Let" andalso argc >= 2 then
             IConst (`I tptp_let, T, [])
           else
             (case proxify_const s of