Question 26099: An Explicit Smaller Cover Refutes Minimum Cardinality

Original question and givens

Use complete unique vertices=[v0, v1, v2, v3, v4, v5, v6, v7, v8] and loop-free duplicate-free undirected edges=[[v0, v1], [v0, v2], [v0, v3], [v0, v4], [v0, v5], [v0, v6], [v0, v7], [v0, v8]], candidate cover=[v0, v1, v2, v3, v4, v5, v6, v7, v8]. An edge needs at least one selected endpoint. Preserve source canonical subset order. Give (candidate, cover, candidate_size, minimum_size, smaller_cover, minimum, certificate).

• G001 — Use complete unique vertices=[v0, v1, v2, v3, v4, v5, v6, v7, v8] and loop-free duplicate-free undirected edges=[[v0, v1], [v0, v2], [v0, v3], [v0, v4], [v0, v5], [v0, v6], [v0, v7], [v0, v8]], candidate cover=[v0, v1, v2, v3, v4, v5, v6, v7, v8]. An edge needs at least one selected endpoint. Preserve source canonical subset order. Give (candidate, cover, candidate_size, minimum_size, smaller_cover, minimum, certificate).

Definition and scope

Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.

• mko-minimum-vertex-cover

Step-by-step derivation

source roles = [mincover-nonminimum-witness]

derived = [[candidate, cover, candidate_size, minimum_size, smaller_cover, minimum, certificate]]

source roles = [[v0, v1, v2, v3, v4, v5, v6, v7, v8], [[v0, v1], [v0, v2], [v0, v3], [v0, v4], [v0, v5], [v0, v6], [v0, v7], [v0, v8]], [v0, v1, v2, v3, v4, v5, v6, v7, v8]]

derived = [[v0, v1, v2, v3, v4, v5, v6, v7, v8], [[v0, v1], [v0, v2], [v0, v3], [v0, v4], [v0, v5], [v0, v6], [v0, v7], [v0, v8]], [v0, v1, v2, v3, v4, v5, v6, v7, v8]]

source roles = [[v0, v1, v2, v3, v4, v5, v6, v7, v8], [[v0, v1], [v0, v2], [v0, v3], [v0, v4], [v0, v5], [v0, v6], [v0, v7], [v0, v8]], 512]

derived = [[1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189, 191, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, 221, 223, 225, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 253, 255, 257, 259, 261, 263, 265, 267, 269, 271, 273, 275, 277, 279, 281, 283, 285, 287, 289, 291, 293, 295, 297, 299, 301, 303, 305, 307, 309, 311, 313, 315, 317, 319, 321, 323, 325, 327, 329, 331, 333, 335, 337, 339, 341, 343, 345, 347, 349, 351, 353, 355, 357, 359, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 385, 387, 389, 391, 393, 395, 397, 399, 401, 403, 405, 407, 409, 411, 413, 415, 417, 419, 421, 423, 425, 427, 429, 431, 433, 435, 437, 439, 441, 443, 445, 447, 449, 451, 453, 455, 457, 459, 461, 463, 465, 467, 469, 471, 473, 475, 477, 479, 481, 483, 485, 487, 489, 491, 493, 495, 497, 499, 501, 503, 505, 507, 509, 510, 511], [[0, 0], [2, 1], [4, 0], [6, 2], [8, 0], [10, 1], [12, 0], [14, 3], [16, 0], [18, 1], [20, 0], [22, 2], [24, 0], [26, 1], [28, 0], [30, 4], [32, 0], [34, 1], [36, 0], [38, 2], [40, 0], [42, 1], [44, 0], [46, 3], [48, 0], [50, 1], [52, 0], [54, 2], [56, 0], [58, 1], [60, 0], [62, 5], [64, 0], [66, 1], [68, 0], [70, 2], [72, 0], [74, 1], [76, 0], [78, 3], [80, 0], [82, 1], [84, 0], [86, 2], [88, 0], [90, 1], [92, 0], [94, 4], [96, 0], [98, 1], [100, 0], [102, 2], [104, 0], [106, 1], [108, 0], [110, 3], [112, 0], [114, 1], [116, 0], [118, 2], [120, 0], [122, 1], [124, 0], [126, 6], [128, 0], [130, 1], [132, 0], [134, 2], [136, 0], [138, 1], [140, 0], [142, 3], [144, 0], [146, 1], [148, 0], [150, 2], [152, 0], [154, 1], [156, 0], [158, 4], [160, 0], [162, 1], [164, 0], [166, 2], [168, 0], [170, 1], [172, 0], [174, 3], [176, 0], [178, 1], [180, 0], [182, 2], [184, 0], [186, 1], [188, 0], [190, 5], [192, 0], [194, 1], [196, 0], [198, 2], [200, 0], [202, 1], [204, 0], [206, 3], [208, 0], [210, 1], [212, 0], [214, 2], [216, 0], [218, 1], [220, 0], [222, 4], [224, 0], [226, 1], [228, 0], [230, 2], [232, 0], [234, 1], [236, 0], [238, 3], [240, 0], [242, 1], [244, 0], [246, 2], [248, 0], [250, 1], [252, 0], [254, 7], [256, 0], [258, 1], [260, 0], [262, 2], [264, 0], [266, 1], [268, 0], [270, 3], [272, 0], [274, 1], [276, 0], [278, 2], [280, 0], [282, 1], [284, 0], [286, 4], [288, 0], [290, 1], [292, 0], [294, 2], [296, 0], [298, 1], [300, 0], [302, 3], [304, 0], [306, 1], [308, 0], [310, 2], [312, 0], [314, 1], [316, 0], [318, 5], [320, 0], [322, 1], [324, 0], [326, 2], [328, 0], [330, 1], [332, 0], [334, 3], [336, 0], [338, 1], [340, 0], [342, 2], [344, 0], [346, 1], [348, 0], [350, 4], [352, 0], [354, 1], [356, 0], [358, 2], [360, 0], [362, 1], [364, 0], [366, 3], [368, 0], [370, 1], [372, 0], [374, 2], [376, 0], [378, 1], [380, 0], [382, 6], [384, 0], [386, 1], [388, 0], [390, 2], [392, 0], [394, 1], [396, 0], [398, 3], [400, 0], [402, 1], [404, 0], [406, 2], [408, 0], [410, 1], [412, 0], [414, 4], [416, 0], [418, 1], [420, 0], [422, 2], [424, 0], [426, 1], [428, 0], [430, 3], [432, 0], [434, 1], [436, 0], [438, 2], [440, 0], [442, 1], [444, 0], [446, 5], [448, 0], [450, 1], [452, 0], [454, 2], [456, 0], [458, 1], [460, 0], [462, 3], [464, 0], [466, 1], [468, 0], [470, 2], [472, 0], [474, 1], [476, 0], [478, 4], [480, 0], [482, 1], [484, 0], [486, 2], [488, 0], [490, 1], [492, 0], [494, 3], [496, 0], [498, 1], [500, 0], [502, 2], [504, 0], [506, 1], [508, 0]], [[v0], [v0, v1], [v0, v2], [v0, v1, v2], [v0, v3], [v0, v1, v3], [v0, v2, v3], [v0, v1, v2, v3], [v0, v4], [v0, v1, v4], [v0, v2, v4], [v0, v1, v2, v4], [v0, v3, v4], [v0, v1, v3, v4], [v0, v2, v3, v4], [v0, v1, v2, v3, v4], [v0, v5], [v0, v1, v5], [v0, v2, v5], [v0, v1, v2, v5], [v0, v3, v5], [v0, v1, v3, v5], [v0, v2, v3, v5], [v0, v1, v2, v3, v5], [v0, v4, v5], [v0, v1, v4, v5], [v0, v2, v4, v5], [v0, v1, v2, v4, v5], [v0, v3, v4, v5], [v0, v1, v3, v4, v5], [v0, v2, v3, v4, v5], [v0, v1, v2, v3, v4, v5], [v0, v6], [v0, v1, v6], [v0, v2, v6], [v0, v1, v2, v6], [v0, v3, v6], [v0, v1, v3, v6], [v0, v2, v3, v6], [v0, v1, v2, v3, v6], [v0, v4, v6], [v0, v1, v4, v6], [v0, v2, v4, v6], [v0, v1, v2, v4, v6], [v0, v3, v4, v6], [v0, v1, v3, v4, v6], [v0, v2, v3, v4, v6], [v0, v1, v2, v3, v4, v6], [v0, v5, v6], [v0, v1, v5, v6], [v0, v2, v5, v6], [v0, v1, v2, v5, v6], [v0, v3, v5, v6], [v0, v1, v3, v5, v6], [v0, v2, v3, v5, v6], [v0, v1, v2, v3, v5, v6], [v0, v4, v5, v6], [v0, v1, v4, v5, v6], [v0, v2, v4, v5, v6], [v0, v1, v2, v4, v5, v6], [v0, v3, v4, v5, v6], [v0, v1, v3, v4, v5, v6], [v0, v2, v3, v4, v5, v6], [v0, v1, v2, v3, v4, v5, v6], [v0, v7], [v0, v1, v7], [v0, v2, v7], [v0, v1, v2, v7], [v0, v3, v7], [v0, v1, v3, v7], [v0, v2, v3, v7], [v0, v1, v2, v3, v7], [v0, v4, v7], [v0, v1, v4, v7], [v0, v2, v4, v7], [v0, v1, v2, v4, v7], [v0, v3, v4, v7], [v0, v1, v3, v4, v7], [v0, v2, v3, v4, v7], [v0, v1, v2, v3, v4, v7], [v0, v5, v7], [v0, v1, v5, v7], [v0, v2, v5, v7], [v0, v1, v2, v5, v7], [v0, v3, v5, v7], [v0, v1, v3, v5, v7], [v0, v2, v3, v5, v7], [v0, v1, v2, v3, v5, v7], [v0, v4, v5, v7], [v0, v1, v4, v5, v7], [v0, v2, v4, v5, v7], [v0, v1, v2, v4, v5, v7], [v0, v3, v4, v5, v7], [v0, v1, v3, v4, v5, v7], [v0, v2, v3, v4, v5, v7], [v0, v1, v2, v3, v4, v5, v7], [v0, v6, v7], [v0, v1, v6, v7], [v0, v2, v6, v7], [v0, v1, v2, v6, v7], [v0, v3, v6, v7], [v0, v1, v3, v6, v7], [v0, v2, v3, v6, v7], [v0, v1, v2, v3, v6, v7], [v0, v4, v6, v7], [v0, v1, v4, v6, v7], [v0, v2, v4, v6, v7], [v0, v1, v2, v4, v6, v7], [v0, v3, v4, v6, v7], [v0, v1, v3, v4, v6, v7], [v0, v2, v3, v4, v6, v7], [v0, v1, v2, v3, v4, v6, v7], [v0, v5, v6, v7], [v0, v1, v5, v6, v7], [v0, v2, v5, v6, v7], [v0, v1, v2, v5, v6, v7], [v0, v3, v5, v6, v7], [v0, v1, v3, v5, v6, v7], [v0, v2, v3, v5, v6, v7], [v0, v1, v2, v3, v5, v6, v7], [v0, v4, v5, v6, v7], [v0, v1, v4, v5, v6, v7], [v0, v2, v4, v5, v6, v7], [v0, v1, v2, v4, v5, v6, v7], [v0, v3, v4, v5, v6, v7], [v0, v1, v3, v4, v5, v6, v7], [v0, v2, v3, v4, v5, v6, v7], [v0, v1, v2, v3, v4, v5, v6, v7], [v0, v8], [v0, v1, v8], [v0, v2, v8], [v0, v1, v2, v8], [v0, v3, v8], [v0, v1, v3, v8], [v0, v2, v3, v8], [v0, v1, v2, v3, v8], [v0, v4, v8], [v0, v1, v4, v8], [v0, v2, v4, v8], [v0, v1, v2, v4, v8], [v0, v3, v4, v8], [v0, v1, v3, v4, v8], [v0, v2, v3, v4, v8], [v0, v1, v2, v3, v4, v8], [v0, v5, v8], [v0, v1, v5, v8], [v0, v2, v5, v8], [v0, v1, v2, v5, v8], [v0, v3, v5, v8], [v0, v1, v3, v5, v8], [v0, v2, v3, v5, v8], [v0, v1, v2, v3, v5, v8], [v0, v4, v5, v8], [v0, v1, v4, v5, v8], [v0, v2, v4, v5, v8], [v0, v1, v2, v4, v5, v8], [v0, v3, v4, v5, v8], [v0, v1, v3, v4, v5, v8], [v0, v2, v3, v4, v5, v8], [v0, v1, v2, v3, v4, v5, v8], [v0, v6, v8], [v0, v1, v6, v8], [v0, v2, v6, v8], [v0, v1, v2, v6, v8], [v0, v3, v6, v8], [v0, v1, v3, v6, v8], [v0, v2, v3, v6, v8], [v0, v1, v2, v3, v6, v8], [v0, v4, v6, v8], [v0, v1, v4, v6, v8], [v0, v2, v4, v6, v8], [v0, v1, v2, v4, v6, v8], [v0, v3, v4, v6, v8], [v0, v1, v3, v4, v6, v8], [v0, v2, v3, v4, v6, v8], [v0, v1, v2, v3, v4, v6, v8], [v0, v5, v6, v8], [v0, v1, v5, v6, v8], [v0, v2, v5, v6, v8], [v0, v1, v2, v5, v6, v8], [v0, v3, v5, v6, v8], [v0, v1, v3, v5, v6, v8], [v0, v2, v3, v5, v6, v8], [v0, v1, v2, v3, v5, v6, v8], [v0, v4, v5, v6, v8], [v0, v1, v4, v5, v6, v8], [v0, v2, v4, v5, v6, v8], [v0, v1, v2, v4, v5, v6, v8], [v0, v3, v4, v5, v6, v8], [v0, v1, v3, v4, v5, v6, v8], [v0, v2, v3, v4, v5, v6, v8], [v0, v1, v2, v3, v4, v5, v6, v8], [v0, v7, v8], [v0, v1, v7, v8], [v0, v2, v7, v8], [v0, v1, v2, v7, v8], [v0, v3, v7, v8], [v0, v1, v3, v7, v8], [v0, v2, v3, v7, v8], [v0, v1, v2, v3, v7, v8], [v0, v4, v7, v8], [v0, v1, v4, v7, v8], [v0, v2, v4, v7, v8], [v0, v1, v2, v4, v7, v8], [v0, v3, v4, v7, v8], [v0, v1, v3, v4, v7, v8], [v0, v2, v3, v4, v7, v8], [v0, v1, v2, v3, v4, v7, v8], [v0, v5, v7, v8], [v0, v1, v5, v7, v8], [v0, v2, v5, v7, v8], [v0, v1, v2, v5, v7, v8], [v0, v3, v5, v7, v8], [v0, v1, v3, v5, v7, v8], [v0, v2, v3, v5, v7, v8], [v0, v1, v2, v3, v5, v7, v8], [v0, v4, v5, v7, v8], [v0, v1, v4, v5, v7, v8], [v0, v2, v4, v5, v7, v8], [v0, v1, v2, v4, v5, v7, v8], [v0, v3, v4, v5, v7, v8], [v0, v1, v3, v4, v5, v7, v8], [v0, v2, v3, v4, v5, v7, v8], [v0, v1, v2, v3, v4, v5, v7, v8], [v0, v6, v7, v8], [v0, v1, v6, v7, v8], [v0, v2, v6, v7, v8], [v0, v1, v2, v6, v7, v8], [v0, v3, v6, v7, v8], [v0, v1, v3, v6, v7, v8], [v0, v2, v3, v6, v7, v8], [v0, v1, v2, v3, v6, v7, v8], [v0, v4, v6, v7, v8], [v0, v1, v4, v6, v7, v8], [v0, v2, v4, v6, v7, v8], [v0, v1, v2, v4, v6, v7, v8], [v0, v3, v4, v6, v7, v8], [v0, v1, v3, v4, v6, v7, v8], [v0, v2, v3, v4, v6, v7, v8], [v0, v1, v2, v3, v4, v6, v7, v8], [v0, v5, v6, v7, v8], [v0, v1, v5, v6, v7, v8], [v0, v2, v5, v6, v7, v8], [v0, v1, v2, v5, v6, v7, v8], [v0, v3, v5, v6, v7, v8], [v0, v1, v3, v5, v6, v7, v8], [v0, v2, v3, v5, v6, v7, v8], [v0, v1, v2, v3, v5, v6, v7, v8], [v0, v4, v5, v6, v7, v8], [v0, v1, v4, v5, v6, v7, v8], [v0, v2, v4, v5, v6, v7, v8], [v0, v1, v2, v4, v5, v6, v7, v8], [v0, v3, v4, v5, v6, v7, v8], [v0, v1, v3, v4, v5, v6, v7, v8], [v0, v2, v3, v4, v5, v6, v7, v8], [v1, v2, v3, v4, v5, v6, v7, v8], [v0, v1, v2, v3, v4, v5, v6, v7, v8]], [0, 1, 8, 28, 56, 70, 56, 28, 9, 1], 1, [[v0]]]

source roles = [[v0, v1, v2, v3, v4, v5, v6, v7, v8], [[v0, v1], [v0, v2], [v0, v3], [v0, v4], [v0, v5], [v0, v6], [v0, v7], [v0, v8]]]

derived = [[[[v0, v1], Yes], [[v0, v2], Yes], [[v0, v3], Yes], [[v0, v4], Yes], [[v0, v5], Yes], [[v0, v6], Yes], [[v0, v7], Yes], [[v0, v8], Yes]], 9, 1, [v0]]

Reverse checks

• S004 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
• S003 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
• S002 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
• S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

([v0, v1, v2, v3, v4, v5, v6, v7, v8], Yes, 9, 1, [v0], No, explicit_smaller_cover_refutes_minimum_status)

The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.

This question review and source binding

Review date: 2026-10-26

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.