diff --git a/test_swarmmetrics.py b/test_swarmmetrics.py
index 6e718fa..982a564 100644
--- a/test_swarmmetrics.py
+++ b/test_swarmmetrics.py
@@ -100,6 +100,41 @@ def test_full_analysis():
     assert len(result.channels) == 1
     assert len(result.nodes) == 2
 
+def test_f32_zombie_broadcast():
+    """F3.2 must rank 5-message dialogue above 100-ping broadcast.
+    Regression test for reticuli's arithmetic proof (Colony, 2026-07-27):
+    F3.1 count*log(1+r) lets volume buy back low reciprocity."""
+    msgs = []
+    # 5-message dialogue, high reciprocity (3+2)
+    for i in range(3):
+        msgs.append({"from_id": "alice", "to_id": "bob", "timestamp": now - 1*day + i*100})
+    for i in range(2):
+        msgs.append({"from_id": "bob", "to_id": "alice", "timestamp": now - 0.5*day + i*100})
+    # 100-ping broadcast, low reciprocity (95+5)
+    for i in range(95):
+        msgs.append({"from_id": "carol", "to_id": "dave", "timestamp": now - 2*day + i*60})
+    for i in range(5):
+        msgs.append({"from_id": "dave", "to_id": "carol", "timestamp": now - 1.5*day + i*600})
+
+    edges = score_reciprocity(msgs, now=now)
+    dialogue = [e for e in edges.values() if "alice" in (e.source, e.target)][0]
+    broadcast = [e for e in edges.values() if "carol" in (e.source, e.target)][0]
+    assert dialogue.reciprocity_f32 > broadcast.reciprocity_f32, \
+        f"F3.2 zombie fail: dialogue={dialogue.reciprocity_f32:.4f} <= broadcast={broadcast.reciprocity_f32:.4f}"
+
+
+def test_f32_idf_echo_combined():
+    """F3.2 and IDF echo work together in full analyze()."""
+    msgs = [
+        {"from_id": "a", "to_id": "b", "timestamp": now - 1*day, "channel": "ch", "concepts": ["rare-concept"]},
+        {"from_id": "b", "to_id": "a", "timestamp": now - 0.9*day, "channel": "ch", "concepts": ["rare-concept"]},
+    ]
+    result = analyze(msgs, now=now)
+    assert len(result.edges) == 1
+    edge = list(result.edges.values())[0]
+    assert edge.reciprocity_f32 > 0, "F3.2 should be positive for reciprocal edge"
+
+
 # Run all tests
 tests = [v for k, v in sorted(globals().items()) if k.startswith("test_")]
 passed = 0