1 files changed, 1 insertions, 1 deletions

diff --git a/readme.md b/readme.md
index f2471ce..559e9a2 100644
--- a/readme.md
+++ b/readme.md
@@ -141,7 +141,7 @@ the number of `Y` is `X`
 ### `X\Y`
 `Y` is subject to the conditions `X`
 
-## `X?/Y`
+### `X?/Y`
 `Y` exists according to/in the perspective of `*X`
 
 # other operators