Add Wichardt 2008 (GEB) to the catalogue

build_support/catalog/catalog.am

@@ -14,6 +14,7 @@ CATALOG_FILES = \
 	catalog/journals/geb/bagwell1995.efg \
 	catalog/journals/geb/gilboa1997/fig1.efg \
 	catalog/journals/geb/gilboa1997/fig2.efg \
+	catalog/journals/geb/wichardt2008.efg \
 	catalog/journals/ijgt/nau2004/sec3.nfg \
 	catalog/journals/ijgt/nau2004/sec4.nfg \
 	catalog/journals/ijgt/nau2004/sec5.nfg \

build_support/catalog/catalog_hierarchy.yaml

@@ -15,6 +15,7 @@ labels:
   books/vonstengel2022: "von Stengel (2022) — Game Theory Basics"
   books/watson2013: "Watson (2013) — Strategy: An Introduction to Game Theory"
   journals/geb/gilboa1997: "Gilboa (1997)"
+  journals/geb/wichardt2008: "Wichardt (2008)"
   journals/ijgt/nau2004: "Nau et al. (2004)"
   journals/ijgt/selten1975: "Selten (1975)"
   journals/mor/vonstengelforges2008: "von Stengel & Forges (2008)"

tests/test_games/wichardt.efg → catalog/journals/geb/wichardt2008.efg

@@ -1,5 +1,6 @@
 EFG 2 R "Wichardt (2008): 2 players, imperfect recall" { "Player 1" "Player 2" }
-""
+"The first counterexample showing that finite extensive-form games
+with imperfect recall need not have a Nash equilibrium in behaviour strategies"
 
 p "" 1 1 "" { "R" "L" } 0
 p "" 1 2 "" { "r" "l" } 0

doc/references.bib

@@ -392,3 +392,15 @@ @inbook{Shap74
   pages     = {175--189},
   category  = {articles_equilibria}
 }
+
+
+@article{Wichardt2008,
+  author    = {Wichardt, P. C.},
+  title     = {Existence of Nash equilibria in finite extensive form games with imperfect recall: A counterexample},
+  journal   = {Games and Economic Behavior},
+  volume    = {63},
+  number    = {1},
+  pages     = {366--369},
+  year      = {2008},
+  category  = {articles_equilibria}
+}

tests/test_extensive.py

@@ -61,7 +61,7 @@ def test_game_add_players_nolabel():
 
     # Games with imperfect recall from files (game_input is a string)
     # - imperfect recall without absent-mindedness
-    ("wichardt.efg", False),  # forgetting past action; Wichardt (GEB, 2008)
+    (gbt.catalog.load("journals/geb/wichardt2008"), False),  # forgetting past action
     ("gilboa_two_am_agents.efg", False),  # forgetting past information; Gilboa (GEB, 1997)
     # - imperfect recall with absent-mindedness
     ("noPR-AM-driver-one-player.efg", False),  # 1 players, one infoset unreached
@@ -370,7 +370,7 @@ def test_outcome_index_exception_label():
         # I M P E R F E C T   R E C A L L --- commented out in the test suite
         # Wichardt (2008): binary tree of height 3; 2 players; the root player forgets the action
         # (
-        #    games.read_from_file("wichardt.efg"),
+        #    gbt.catalog.load("journals/geb/wichardt2008"),
         #    [["11", "12", "21", "22"], ["1", "2"]],
         #    [
         #        np.array([[1, -1], [-5, -5], [-5, -5], [-1, 1]]),

tests/test_infosets.py

@@ -104,7 +104,7 @@ class AbsentMindednessTestCase:
     ),
     pytest.param(
         PriorActionsTestCase(
-            factory=functools.partial(games.read_from_file, "wichardt.efg"),
+            factory=functools.partial(gbt.catalog.load, "journals/geb/wichardt2008"),
             expected_results=[
                 ("Player 1", 0, {None}),
                 ("Player 1", 1, {("Player 1", 0, "L"), ("Player 1", 0, "R")}),
@@ -178,7 +178,7 @@ class AbsentMindednessTestCase:
     ),
     pytest.param(
         AbsentMindednessTestCase(
-            factory=functools.partial(games.read_from_file, "wichardt.efg"),
+            factory=functools.partial(gbt.catalog.load, "journals/geb/wichardt2008"),
             expected_am_paths=[]
         ),
         id="wichardt_forgetting_action"

tests/test_node.py

@@ -150,7 +150,7 @@ class SubgameRootsTestCase:
     # ------------------------------------------------------------------------
     pytest.param(
         SubgameRootsTestCase(
-            factory=functools.partial(games.read_from_file, "wichardt.efg"),
+            factory=functools.partial(gbt.catalog.load, "journals/geb/wichardt2008"),
             expected_paths=[[]]
         ),
         id="wichardt_no_nontrivial_subgames"
@@ -261,7 +261,7 @@ class SubgameStructureTestCase:
     # ------------------------------------------------------------------------
     pytest.param(
         SubgameStructureTestCase(
-            factory=functools.partial(games.read_from_file, "wichardt.efg"),
+            factory=functools.partial(gbt.catalog.load, "journals/geb/wichardt2008"),
             roots=[[]],
             parents={(): None},
             children={(): set()},
@@ -390,7 +390,7 @@ def test_minimal_subgame_for_each_infoset(test_case: SubgameStructureTestCase):
         ]
     ),
     (
-        "wichardt.efg",
+        gbt.catalog.load("journals/geb/wichardt2008"),
         [
             ([], None),
             (["R"], ("Player 1", 0, "R")),
@@ -438,7 +438,7 @@ def test_node_own_prior_action_non_terminal(game_file, expected_node_data):
     Tests `node.own_prior_action` for non-terminal nodes.
     Also verifies that all terminal nodes return None.
     """
-    game = games.read_from_file(game_file)
+    game = game_file if isinstance(game_file, gbt.Game) else games.read_from_file(game_file)
 
     actual_node_data = []
 
@@ -461,7 +461,7 @@ def test_node_own_prior_action_non_terminal(game_file, expected_node_data):
 
 @pytest.mark.parametrize("game_file, expected_unreachable_paths", [
     # Games without absent-mindedness, where all nodes are reachable
-    ("wichardt.efg", []),
+    (gbt.catalog.load("journals/geb/wichardt2008"), []),
     ("subgames.efg", []),
 
     # An absent-minded driver game with an unreachable terminal node
@@ -482,7 +482,7 @@ def test_is_strategy_reachable(game_file: str, expected_unreachable_paths: list[
     converting them to their action-label paths, and comparing the resulting
     list of paths against a known-correct list.
     """
-    game = games.read_from_file(game_file)
+    game = game_file if isinstance(game_file, gbt.Game) else games.read_from_file(game_file)
     nodes = game.nodes
 
     actual_unreachable_paths = [