Clarify soft erosion scaling claim

1 files changed, 11 insertions, 0 deletions

diff --git a/notes/18_contribution_roadmap.md b/notes/18_contribution_roadmap.md
index 4805a19..be4d775 100644
--- a/notes/18_contribution_roadmap.md
+++ b/notes/18_contribution_roadmap.md
@@ -71,6 +71,17 @@ So the FA/BP gap need not wait until redundant directions are fully exhausted.
 Redundancy suppresses the expected task-relevant alignment burden, but does not
 make it exactly zero.
 
+The scaling distinction is:
+
+```text
+k fixed, P grows        -> k/P -> 0, erosion vanishes
+k proportional to P     -> k/P stays constant, relative erosion persists
+```
+
+For equal-width MLPs, both parameter count and feedback matrix dimensions scale
+like `Θ(L n^2)`, so a fixed per-matrix alignment burden can remain a constant
+fraction of capacity under width scaling.
+
 Hard functional rank loss remains a limiting sanity check:
 
 ```text