# 第 22401 題：下推自動機 [返回所在分頁 113](https://ocme.evemisslab.com/zh-Hant/questions/page/113/) [← 逐題詳解目錄](https://ocme.evemisslab.com/zh-Hant/questions/) · [原題批次](https://ocme.evemisslab.com/zh-Hant/practice/batch-20261014-advance-20261110-r07-pushdown-automaton-foundations/#q-20261014-advance-20261110-r07-pushdown-automaton-0051) 本頁是已完成第二對話 AI 數理與中英語義覆核的教學詳解，只支持本題明示的模型與前提。沒有人工審查或新 Lean 證明，也不提升原題或 MKO 的 Canonical 真值狀態。 R0043-22401 · q-20261014-advance-20261110-r07-pushdown-automaton-0051 ## 原題與已知條件 transition=[from,input-or-null,required-top,to,replacement-bottom-to-top]的finite nondeterministic PDA。操作=pda-accepting-run-witness；資料={"states":["push0","pop0","accept0"],"input_alphabet":["a0","b0"],"stack_alphabet":["Z0","A0"],"start_state":"push0","bottom_symbol":"Z0","final_states":["accept0"],"transitions":[["push0","a0","Z0","push0",["Z0","A0"]],["push0","a0","A0","push0",["A0","A0"]],["push0","b0","A0","pop0",[]],["pop0","b0","A0","pop0",[]],["push0",null,"Z0","accept0",["Z0"]],["pop0",null,"Z0","accept0",["Z0"]]],"input":[],"trace":[["push0",0,["Z0"]],["accept0",0,["Z0"]]]}。請依 exact_ordered_tuple_declared_by_interface 欄序回答。 - G001 — transition=[from,input-or-null,required-top,to,replacement-bottom-to-top]的finite nondeterministic PDA。操作=pda-accepting-run-witness；資料={"states":["push0","pop0","accept0"],"input_alphabet":["a0","b0"],"stack_alphabet":["Z0","A0"],"start_state":"push0","bottom_symbol":"Z0","final_states":["accept0"],"transitions":[["push0","a0","Z0","push0",["Z0","A0"]],["push0","a0","A0","push0",["A0","A0"]],["push0","b0","A0","pop0",[]],["pop0","b0","A0","pop0",[]],["push0",null,"Z0","accept0",["Z0"]],["pop0",null,"Z0","accept0",["Z0"]]],"input":[],"trace":[["push0",0,["Z0"]],["accept0",0,["Z0"]]]}。請依 exact_ordered_tuple_declared_by_interface 欄序回答。 ## 定義與適用範圍 沿用原題明示的論域、假設與來源 MKO 定義。本題已完成第二對話數理與中英語義覆核，並由原始參數逐題獨立重算模型、答案與每個算術步驟；原題仍為 candidate。 - [mko-pushdown-automaton](https://ocme.evemisslab.com/zh-Hant/mko/mko-pushdown-automaton/) ## 逐步推導 S001 · implies操作前 source operation=pda-accepting-run-witness;original snapshot and mathematics retained 操作後 explicit ordered source output fields=[input, trace, transition_indices, valid_run, accepted, step_count, certificate] 條件：無 原題歷史介面標記保留，直接列來源有序欄位，不需JavaScript；MVT由原mode選欄序，不補空欄或看答案形狀猜。tag與固定No保原聲稱範圍。 步驟識別與依賴規則：source_ordered_interface_explicit_without_javascript · 依賴：G001 S002 · implies操作前 ORIGINAL transition index=0;[from,input_or_null,required_top,to,replacement_bottom_to_top]=[push0, a0, Z0, push0, [Z0, A0]];bottom=Z0 操作後 states/input/stack symbols legal;null input consumes0;top=bottom requires replacement first bottom,otherwise replacement contains NO bottom;ORIGINAL transition position retained 條件：無 逐原transition核state、input與stack角色，不把字母表混用；null是epsilon而不是一個字母。stack bottom-first/top-last，pop一個top再按原replacement順序append；只施來源明示bottom guard，不另加更強慣例。 步驟識別與依賴規則：pda_EVERY_original_transition_roles_epsilon_bottom_guard · 依賴：G001, S001 S003 · implies操作前 ORIGINAL transition index=1;[from,input_or_null,required_top,to,replacement_bottom_to_top]=[push0, a0, A0, push0, [A0, A0]];bottom=Z0 操作後 states/input/stack symbols legal;null input consumes0;top=bottom requires replacement first bottom,otherwise replacement contains NO bottom;ORIGINAL transition position retained 條件：無 逐原transition核state、input與stack角色，不把字母表混用；null是epsilon而不是一個字母。stack bottom-first/top-last，pop一個top再按原replacement順序append；只施來源明示bottom guard，不另加更強慣例。 步驟識別與依賴規則：pda_EVERY_original_transition_roles_epsilon_bottom_guard · 依賴：G001, S002 S004 · implies操作前 ORIGINAL transition index=2;[from,input_or_null,required_top,to,replacement_bottom_to_top]=[push0, b0, A0, pop0, []];bottom=Z0 操作後 states/input/stack symbols legal;null input consumes0;top=bottom requires replacement first bottom,otherwise replacement contains NO bottom;ORIGINAL transition position retained 條件：無 逐原transition核state、input與stack角色，不把字母表混用；null是epsilon而不是一個字母。stack bottom-first/top-last，pop一個top再按原replacement順序append；只施來源明示bottom guard，不另加更強慣例。 步驟識別與依賴規則：pda_EVERY_original_transition_roles_epsilon_bottom_guard · 依賴：G001, S003 S005 · implies操作前 ORIGINAL transition index=3;[from,input_or_null,required_top,to,replacement_bottom_to_top]=[pop0, b0, A0, pop0, []];bottom=Z0 操作後 states/input/stack symbols legal;null input consumes0;top=bottom requires replacement first bottom,otherwise replacement contains NO bottom;ORIGINAL transition position retained 條件：無 逐原transition核state、input與stack角色，不把字母表混用；null是epsilon而不是一個字母。stack bottom-first/top-last，pop一個top再按原replacement順序append；只施來源明示bottom guard，不另加更強慣例。 步驟識別與依賴規則：pda_EVERY_original_transition_roles_epsilon_bottom_guard · 依賴：G001, S004 S006 · implies操作前 ORIGINAL transition index=4;[from,input_or_null,required_top,to,replacement_bottom_to_top]=[push0, null, Z0, accept0, [Z0]];bottom=Z0 操作後 states/input/stack symbols legal;null input consumes0;top=bottom requires replacement first bottom,otherwise replacement contains NO bottom;ORIGINAL transition position retained 條件：無 逐原transition核state、input與stack角色，不把字母表混用；null是epsilon而不是一個字母。stack bottom-first/top-last，pop一個top再按原replacement順序append；只施來源明示bottom guard，不另加更強慣例。 步驟識別與依賴規則：pda_EVERY_original_transition_roles_epsilon_bottom_guard · 依賴：G001, S005 S007 · implies操作前 ORIGINAL transition index=5;[from,input_or_null,required_top,to,replacement_bottom_to_top]=[pop0, null, Z0, accept0, [Z0]];bottom=Z0 操作後 states/input/stack symbols legal;null input consumes0;top=bottom requires replacement first bottom,otherwise replacement contains NO bottom;ORIGINAL transition position retained 條件：無 逐原transition核state、input與stack角色，不把字母表混用；null是epsilon而不是一個字母。stack bottom-first/top-last，pop一個top再按原replacement順序append；只施來源明示bottom guard，不另加更強慣例。 步驟識別與依賴規則：pda_EVERY_original_transition_roles_epsilon_bottom_guard · 依賴：G001, S006 S008 · calculation操作前 PDA complete ORIGINAL transition count := sum(1, 1, 1, 1, 1, 1) 操作後 PDA complete ORIGINAL transition count = 6 條件：無 依原始角色、次序與已核中間量精確代值；不改source binding或用浮點近似。 步驟識別與依賴規則：exact_rational_arithmetic · 依賴：G001, S007 S009 · implies操作前 ORIGINAL states=[push0, pop0, accept0],input alphabet=[a0, b0],stack alphabet=[Z0, A0];start=push0,bottom=Z0,final states=[accept0] 操作後 finite unique pairwise-disjoint alphabets qualified;transition count=6;acceptance convention FULL input in final state,NOT empty stack;qualification alone proves NO run,determinism or CFG equivalence 條件：無 有限完整定義的資格不等於存在接受run，也不推deterministic或CFG等價。接受時可保非空stack（至少bottom），但必須讀完整input到final。 步驟識別與依賴規則：pda_complete_definition_not_determinism_or_accepting_run · 依賴：G001, S008 S010 · implies操作前 ORIGINAL input=[];ALL source configurations=[[push0, 0, [Z0]], [accept0, 0, [Z0]]];declared start=push0,bottom=Z0 操作後 first configuration EXACTLY=[push0, 0, [Z0]];all state/position/stack values legal;this is NOT yet a valid-run or acceptance certificate 條件：無 初始state、input位置0及單一bottom必恰等來源；全部config先核合法，再逐步驗transition。合法config列表不保證相鄰步驟相容。 步驟識別與依賴規則：pda_trace_ALL_configurations_qualified_actual_initial_required · 依賴：G001, S009 S011 · implies操作前 ORIGINAL trace step=0;from=[push0, 0, [Z0]];to=[accept0, 0, [Z0]];actual input=[] 操作後 ALL [ORIGINAL transition index,applied_result_or_null]=[[0, null], [1, null], [2, null], [3, null], [4, [accept0, 0, [Z0]]], [5, null]];FIRST matching index=4 條件：無 逐原transition順序選第一個真產生nextconfig者；input-or-null決定是否消耗，stack只換top並保replacement次序。失敗保先前partial indices，後面的final state不能修好錯步。 步驟識別與依賴規則：pda_each_actual_stack_update_FIRST_original_transition · 依賴：G001, S010 S012 · implies操作前 ORIGINAL last config=[accept0, 0, [Z0]];input length=0;matched prior indices=[4] 操作後 valid_run=是;FULL input consumed=是;last state final=是;accepted=是;residual stack may be NONEMPTY 條件：無 接受是合法完整run、讀完input、到final三責任合取；可留bottom或其他stack符號。valid與accepted不同，tag標籤本身不把False變成證書。 步驟識別與依賴規則：pda_run_validity_full_consumption_final_state_SEPARATE · 依賴：G001, S011 S013 · calculation操作前 PDA ORIGINAL full trace length minus one := sub(2, 1) 操作後 PDA ORIGINAL full trace length minus one = 1 條件：無 依原始角色、次序與已核中間量精確代值；不改source binding或用浮點近似。 步驟識別與依賴規則：exact_rational_arithmetic · 依賴：G001, S012 S014 · implies操作前 ORIGINAL trace configuration count=2;actual matched transition-index count=1;accepted=是 操作後 SOURCE step_count=ORIGINAL trace.length-1=1;does NOT substitute partial matched count;acceptedTrue is a finite witness,not search completeness 條件：無 原step_count按整份trace長度，即使部分步驟失敗也不改成matched次數。只有accepted=True才由完整有限run證接受，不推所有run、最短或搜尋完整。 步驟識別與依賴規則：pda_original_step_count_not_partial_matched_count · 依賴：G001, S013 ## 逐步反向核對 - S014 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S013 · premise_and_result_audit — 以精確有理數重算 PDA ORIGINAL full trace length minus one，不以小數近似替代。 - S012 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S011 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S010 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S009 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S008 · premise_and_result_audit — 以精確有理數重算 PDA complete ORIGINAL transition count，不以小數近似替代。 - S007 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S006 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S005 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S004 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S003 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S002 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 - S001 · premise_and_result_audit — 回到原始資料與本步條件核對，不把單向推論誤稱等價。 ## 結論 ([], [[push0, 0, [Z0]], [accept0, 0, [Z0]]], [4], 是, 是, 1, finite_full_run_witness_proves_acceptance_under_final_state_convention) 依上列完整代值及條件核對得到原題答案；原題編號、格式與狀態保持不變。 ## 本題覆核與來源綁定 覆核日期：2026-10-26 原題、答案、步驟表達式、數值 AST 與既有歷史保持原樣；原來的候選狀態屬於來源歷史，不覆寫為形式化證明。 來源雜湊與覆核憑證 - input commit: 0f7be61e2c22317a4075561dc822c87d881a50db - original question SHA-256: dc8a15d54e01d27f8683ca90cd7a950fabb5cc92942dc5d2da16d0dcbad1f30a - candidate record SHA-256: e1ff18fecb34c55e3ee2bf05de3d8818a0f182171d2b0f69095272b3b1b882d1 - semantic review receipt SHA-256: 49cf6ec60211c92d1c0c302663af4d44479635dc8181fb61a20c3374288e21c5 - question-first witness SHA-256: 10fd25b4643e5ff12753daceaa61f9f2499bf381f65ef96e9d21185c7c0d0c5e - Lean: NOT_RUN · human review: NOT_PERFORMED [同源完整 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