D-BAG-FOLD evidence: multi-hop existence from resident presence (lab)

.claude/board/FRUITS.md

@@ -4,7 +4,7 @@ Generated by `.claude/tools/fruits_index.py --write`. Do not hand-edit:
 add or change a `**Fruit:**` line on the ledger row and regenerate.
 CI fails when this file is stale.
 
-Open: 35. Closed: 1.
+Open: 36. Closed: 1.
 
 ## discovery torque
 
@@ -42,6 +42,7 @@ _none open_
 
 | tier | row | status | ledger |
 |---|---|---|---|
+| High-signal | ISS-MULTIHOP-PRESENCE-ARM-UNRULED — projection or lens for multi-hop existence? (2026-11-03) | OPEN (operator decision). **Basis:** MEASURED (`.claude/probes/2026-11-03-d-bag-fold/`, `entries/2026-11-03-d-bag-fold-witnessed-existential.md`). | `ISSUES.md` |
 | High-signal | ISS-SOURCE-ROOT-AGENT-OR-REPORT — is a source root the observer or one report? (2026-10-31) | OPEN (operator decision). **Basis:** VERIFIED-IN-CODE (`crates/xlog-relcomp-probe/tests/provenance.rs` `root()` hashes the observer and the report's facts; `unrelated_sources_never_collapse_to_one_root` pins that one observer with two different reports gives two roots). | `ISSUES.md` |
 | High-signal | ISS-RECIPE-LOCO-VOCABULARY-EXISTS-TWICE — two `impl Vocabulary` claim the same 34 op bytes and disagree (2026-10-26) | OPEN (latent). **Basis:** VERIFIED-IN-CODE (OGAR `crates/ogar-loco/src/nars.rs:133-175`, read at OGAR `68cb29b`; lance-graph `crates/lance-graph-ogar/src/recipe_vocab.rs:134-185`, read at `main` `87b2899b`). | `ISSUES.md` |
 | High-signal | ISS-SIX-DECISIONS-NOT-EXECUTED-ACTION-GATE — `commit` still fails open where the decision says fail closed (2026-10-23) | OPEN. **Basis:** VERIFIED-IN-CODE (`crates/lance-graph-contract/src/action.rs:266` `pub fn commit`, `:328` `pub fn commit_via`; read at `main` `19c1324a`). | `ISSUES.md` |

.claude/board/ISSUES.md

@@ -1,3 +1,14 @@
+## ISS-MULTIHOP-PRESENCE-ARM-UNRULED — projection or lens for multi-hop existence? (2026-11-03)
+
+**Status:** OPEN (operator decision). **Basis:** MEASURED (`.claude/probes/2026-11-03-d-bag-fold/`, `entries/2026-11-03-d-bag-fold-witnessed-existential.md`).
+**Fruit:** High-signal
+
+- `∃d R∧S∧T` evaluates in one Program from resident presence in two arms; both match an oracle on 8 cases.
+- Arm P (ADMISSION B prepared projection) is gather-free but copies presence bits; the later zero-copy law admits only `$i`.
+- Arm L (`$i` + `Filter::Semijoin` over the table's own planes) is zero-copy but executes `MaskOp::Gather`, which waits on call-site classification (EXO-140).
+- Both depend on two unenforced invariants: plane order (`ISS-WITNESSED-RANGE-DOES-NOT-ATTEST-PLANE-ORDER`) and presence version (no contract witness).
+- **What closes it:** the ruling on P vs L, then a witness naming the aligned planes; the probe's unchecked arms (cases 5, 8) must become refusals.
+
 ## ISS-SOURCE-ROOT-AGENT-OR-REPORT — is a source root the observer or one report? (2026-10-31)
 
 **Status:** OPEN (operator decision). **Basis:** VERIFIED-IN-CODE (`crates/xlog-relcomp-probe/tests/provenance.rs` `root()` hashes the observer and the report's facts; `unrelated_sources_never_collapse_to_one_root` pins that one observer with two different reports gives two roots).

.claude/board/entries/2026-11-03-d-bag-fold-witnessed-existential.md

@@ -0,0 +1,16 @@
+# 2026-11-03 — D-BAG-FOLD: multi-hop existence from resident presence, no stored relation
+
+**Status:** MEASURED, lab only (`.claude/probes/2026-11-03-d-bag-fold/`, source `514948203`, rustc 1.99.0). No production change; implementation not authorized.
+
+- **Falsified.** A key-prefix range is not edge membership. Prefix-only existence says true with R or S deleted. `Count` over a range is not DISTINCT when keys repeat. A concept-only prefix crosses classids.
+- **Executed.** `∃d R(a,b(d)) ∧ S(b(d),c(d)) ∧ T(c(d),d)` and the count of distinct valid `d` evaluate in ONE Program, with no composed relation, tuple or mask handoff, in two arms:
+  - **P:** an ADMISSION B prepared projection of each relation's own presence, then a row-aligned `And → Any/Count`, gather-free.
+  - **L:** pointer tables `$i` plus `Filter::Semijoin` over the table's own resident planes, zero-copy, executing `MaskOp::Gather`.
+
+  Both arms agree with a nested-loop oracle on 8 cases (each edge deleted, multiple candidates with one or none valid, branch-crossing decoys, another classid, version change). Disabling either Semijoin goes red.
+- **Conditional.** Plane order, key uniqueness and presence version are each a silent wrong answer when unchecked (measured). No contract witness covers plane order (`ISS-WITNESSED-RANGE-DOES-NOT-ATTEST-PLANE-ORDER`) or presence version.
+- **Blocked by rulings, not capability.**
+  - Arm P copies presence bits, which ADMISSION B permits and the later zero-copy law does not.
+  - Arm L needs the `Gather` call-site classification (EXO-140, no owner).
+  - The DT64 route is refused at `r2il::prepare` (`GuardNotExecutable`), and no admitted DO word shape expresses the conjunction (`xlog::bag_count_admitted` admits only `[GroupCount, GroupCount, MulI64]`).
+- **OPEN.** The P-vs-L operator ruling; a plane-naming witness; a mint guard that edges refine their source key. EXO-108 untouched.

.claude/board/entries/README.md

@@ -25,10 +25,11 @@ index row, (3) no duplicate entry id. Checks 1 and 2 are deliberately
 opposite directions; the stranding this convention prevents shows up in
 exactly one of them, never both.
 
-558 entries, 2026-08-06 .. 2026-11-03.
+559 entries, 2026-08-06 .. 2026-11-03.
 
 | date | entry id | finding | file |
 |---|---|---|---|
+| 2026-11-03 | `D-BAG-FOLD` |  | [2026-11-03-d-bag-fold-witnessed-existential.md](2026-11-03-d-bag-fold-witnessed-existential.md) |
 | 2026-11-03 | `a10-writers-retract-xlog-pr` |  | [2026-11-03-a10-writers-retract-xlog-pr.md](2026-11-03-a10-writers-retract-xlog-pr.md) |
 | 2026-11-02 | `sgr-recovery-gates` |  | [2026-11-02-sgr-recovery-gates.md](2026-11-02-sgr-recovery-gates.md) |
 | 2026-11-02 | `p4-thought-git-codegraph-dt64-review` |  | [2026-11-02-p4-thought-git-codegraph-dt64-review.md](2026-11-02-p4-thought-git-codegraph-dt64-review.md) |