Adding sharing validator tool

Cargo.toml

@@ -9,7 +9,7 @@ repository = "https://github.com/adam-Vandervorst/pathMap/"
 keywords = ["trie", "MORK", "path", "algebra"]
 categories = ["algorithms", "data-structures", "database-implementations"]
 readme = "README.md"
-exclude = ["target/", "benches/", "pathmap-book/", ".*"]
+exclude = ["target/", "benches/", "validation/", "pathmap-book/", ".*"]
 
 [package.metadata.docs.rs]
 rustc-args = ["-C", "target-feature=+aes,+sse2"]
@@ -156,5 +156,5 @@ name = "act_line_cache"
 required-features = ["arena_compact", "serialization"]
 
 [workspace]
-members = ["pathmap-derive", "examples/sampling", "examples/arena_compact_tests", "differential"]
+members = ["pathmap-derive", "examples/sampling", "examples/arena_compact_tests", "differential", "validation/algebra_sharing"]
 resolver = "2"

validation/README.md

@@ -0,0 +1,13 @@
+# Algebraic sharing validator
+
+[`algebra_sharing/`](algebra_sharing/) generates related tries and sequences of
+algebraic operations. It checks logical results and identifies steps that lose
+ordinary sharing or miss an opportunity for result sharing. Run
+`cargo run -p algebra-sharing-validation` from the repository root. Ordinary
+and result-sharing losses are counted in the default **report** mode, which
+checks every selected seed and prints aggregate counts. It shows only the first
+four split examples of each kind, clearly labeled in the output. Set
+`PATHMAP_SHARING_ENFORCE_ORDINARY=1` for **strict** mode, which stops at the
+first ordinary-sharing loss and saves a minimized replay. The
+[`source documentation`](algebra_sharing/src/main.rs) explains its model,
+parameters, and replay commands.

validation/algebra_sharing/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "algebra-sharing-validation"
+version = "0.1.0"
+edition = "2024"
+publish = false
+description = "Developer validation of sharing across pathmap algebraic operations"
+
+[dependencies]
+pathmap = { path = "../.." }