{
  "schema_version": "ocme-derivation-reader-v1",
  "guide_id": "derivation-mko-dual-vector-space-01",
  "mko_id": "mko-dual-vector-space",
  "title": {
    "zh-Hant": "雙基底與covector換基",
    "en": "Dual basis and covector change"
  },
  "contract": {
    "schema_version": "ocme-derivation-guide-v0.1",
    "guide_id": "derivation-mko-dual-vector-space-01",
    "source": {
      "mko_id": "mko-dual-vector-space",
      "commit": "b1b2f1dcf8c50d67a93fe52d95f8eef7b3abba9f",
      "sha256": "1994bbbcc73dff239e5c7cfdaba60f5dc5aadb1a0a4603f613e4b1371d59234a",
      "english_sha256": "1e23ee2fa2f740284ff7f2e81139957b6196a81326cb161bae3a56d54fe07153"
    },
    "mode": "worked_example",
    "audience_prerequisites": [
      "calc"
    ],
    "goal": {
      "zh-Hant": "對b₁=(1,1)、b₂=(1,−1)，φ₁=(x+y)/2、φ₂=(x−y)/2為雙基底。",
      "en": "For b1=(1,1),b2=(1,-1), phi1=(x+y)/2,phi2=(x-y)/2 form the dual basis."
    },
    "givens": [
      {
        "id": "G1",
        "statement": {
          "zh-Hant": "V=R²，B=((1,1),(1,−1))，P=[[1,1],[1,−1]]為基底column矩陣。",
          "en": "V=R2, B=((1,1),(1,-1)), P=[[1,1],[1,-1]] is the basis-column matrix."
        }
      }
    ],
    "steps": [
      {
        "id": "S01",
        "uses": [
          "G1"
        ],
        "before_tex": "\\alpha b_1+\\beta b_2=(\\alpha+\\beta,\\alpha-\\beta)",
        "after_tex": "(x,y)=\\frac{x+y}{2}b_1+\\frac{x-y}{2}b_2\\text{ uniquely}",
        "relation": "implies",
        "rule": "calc",
        "conditions": [],
        "explanation": {
          "zh-Hant": "每個座標有唯一這種表示，先認證B為基底。",
          "en": "Every vector has this unique representation, qualifying B as a basis first."
        },
        "reverse_audit": {
          "kind": "premise_audit",
          "required_ids": [
            "G1"
          ],
          "explanation": {
            "zh-Hant": "除2合法，未用尚待證的雙基底來證B。",
            "en": "Division by 2 is valid; the dual basis being constructed is not used to qualify B."
          }
        },
        "leaf_basis": "calc"
      },
      {
        "id": "S02",
        "uses": [
          "G1",
          "S01"
        ],
        "before_tex": "\\phi_1(x,y)=\\frac{x+y}{2},\\quad\\phi_2(x,y)=\\frac{x-y}{2}",
        "after_tex": "\\phi_i(au+bv)=a\\phi_i(u)+b\\phi_i(v)\\quad(i=1,2)",
        "relation": "implies",
        "rule": "calc",
        "conditions": [],
        "explanation": {
          "zh-Hant": "固定row covector乘座標，分配律對任意實a、b證線性。",
          "en": "Each fixed row covector is linear by distributivity for all real a,b."
        },
        "reverse_audit": {
          "kind": "premise_audit",
          "required_ids": [
            "G1",
            "S01"
          ],
          "explanation": {
            "zh-Hant": "φᵢ輸出實數；泛函不等同primal向量。",
            "en": "phi_i returns a real number; a functional is not a primal vector."
          }
        },
        "leaf_basis": "calc"
      },
      {
        "id": "S03",
        "uses": [
          "G1",
          "S02"
        ],
        "before_tex": "b_1=(1,1)",
        "after_tex": "\\phi_1(b_1)=1,\\quad\\phi_2(b_1)=0",
        "relation": "implies",
        "rule": "calc",
        "conditions": [],
        "explanation": {
          "zh-Hant": "代入第一基底向量，核第一column的delta值。",
          "en": "Evaluating the first basis vector checks the first delta column."
        },
        "reverse_audit": {
          "kind": "premise_audit",
          "required_ids": [
            "G1",
            "S02"
          ],
          "explanation": {
            "zh-Hant": "(1−1)/2為0，不能兩格皆1。",
            "en": "(1-1)/2 is zero; both entries cannot be one."
          }
        },
        "leaf_basis": "calc"
      },
      {
        "id": "S04",
        "uses": [
          "G1",
          "S02",
          "S03"
        ],
        "before_tex": "b_2=(1,-1)",
        "after_tex": "\\phi_1(b_2)=0,\\quad\\phi_2(b_2)=1",
        "relation": "implies",
        "rule": "calc",
        "conditions": [],
        "explanation": {
          "zh-Hant": "代入第二基底向量，四pairings矩陣完整為I₂。",
          "en": "Evaluating the second vector completes the four-pairing matrix I2."
        },
        "reverse_audit": {
          "kind": "premise_audit",
          "required_ids": [
            "G1",
            "S02",
            "S03"
          ],
          "explanation": {
            "zh-Hant": "φ₂(b₂)=(1−(−1))/2=1，需保留負號。",
            "en": "phi2(b2)=(1-(-1))/2=1, with the minus sign retained."
          }
        },
        "leaf_basis": "calc"
      },
      {
        "id": "S05",
        "uses": [
          "G1",
          "S01",
          "S02",
          "S03",
          "S04"
        ],
        "before_tex": "\\ell\\in V^*,\\quad v=\\alpha b_1+\\beta b_2",
        "after_tex": "\\ell(v)=\\alpha\\ell(b_1)+\\beta\\ell(b_2)=\\ell(b_1)\\phi_1(v)+\\ell(b_2)\\phi_2(v)",
        "relation": "implies",
        "rule": "calc",
        "conditions": [],
        "explanation": {
          "zh-Hant": "任意線性泛函由基底值決定，因此兩φ生成全部V*。",
          "en": "An arbitrary linear functional is determined by its basis values, so the two phi functionals span V*."
        },
        "reverse_audit": {
          "kind": "premise_audit",
          "required_ids": [
            "G1",
            "S01",
            "S02",
            "S03",
            "S04"
          ],
          "explanation": {
            "zh-Hant": "ℓ是任意的，不是只檢查特定幾個函數。",
            "en": "Ell is arbitrary, not a few sampled functions."
          }
        },
        "leaf_basis": "calc"
      },
      {
        "id": "S06",
        "uses": [
          "G1",
          "S03",
          "S04",
          "S05"
        ],
        "before_tex": "a\\phi_1+b\\phi_2=0\\text{ as functions}",
        "after_tex": "\\text{evaluate at }b_1,b_2:\\quad a=b=0",
        "relation": "implies",
        "rule": "mko_definition",
        "conditions": [],
        "explanation": {
          "zh-Hant": "評值直接證獨立，與生成合成真正雙基底。",
          "en": "Evaluation directly proves independence, completing the dual basis with spanning."
        },
        "reverse_audit": {
          "kind": "premise_audit",
          "required_ids": [
            "G1",
            "S03",
            "S04",
            "S05"
          ],
          "explanation": {
            "zh-Hant": "零函數意味所有輸入值皆零，所以可在兩個基底向量核。",
            "en": "The zero functional vanishes on all inputs, so in particular on both basis vectors."
          }
        },
        "leaf_basis": "mko_definition"
      },
      {
        "id": "S07",
        "uses": [
          "G1",
          "S01"
        ],
        "before_tex": "[v]_{\\rm std}=P[v]_B",
        "after_tex": "[v]_B=P^{-1}[v]_{\\rm std},\\quad P^{-1}=\\frac12\\begin{pmatrix}1&1\\\\1&-1\\end{pmatrix}",
        "relation": "implies",
        "rule": "calc",
        "conditions": [],
        "explanation": {
          "zh-Hant": "primal座標乘逆矩陣；P²=2I精確核逆矩陣。",
          "en": "Primal coordinates use the inverse; P^2=2I exactly verifies it."
        },
        "reverse_audit": {
          "kind": "premise_audit",
          "required_ids": [
            "G1",
            "S01"
          ],
          "explanation": {
            "zh-Hant": "P與P^{-1}不可混用，即使本例只差純量。",
            "en": "P and P inverse cannot be interchanged even though they differ by a scalar here."
          }
        },
        "leaf_basis": "calc"
      },
      {
        "id": "S08",
        "uses": [
          "G1",
          "S01",
          "S07"
        ],
        "before_tex": "\\ell(x,y)=3x+y,\\quad[\\ell]_{\\rm std}=(3,1)",
        "after_tex": "[\\ell]_B=(3,1)P=(4,2),\\quad\\ell(v)=4\\alpha+2\\beta",
        "relation": "implies",
        "rule": "calc",
        "conditions": [],
        "explanation": {
          "zh-Hant": "covector row乘P而非P^{-1}，與primal換基方向相反。",
          "en": "The covector row multiplies P rather than P inverse, opposite to primal coordinate change."
        },
        "reverse_audit": {
          "kind": "premise_audit",
          "required_ids": [
            "G1",
            "S01",
            "S07"
          ],
          "explanation": {
            "zh-Hant": "代入x=α+β,y=α−β得4α+2β，核同一泛函。",
            "en": "Substitution x=alpha+beta,y=alpha-beta gives 4alpha+2beta, checking the same functional."
          }
        },
        "leaf_basis": "calc"
      }
    ],
    "result": {
      "zh-Hant": "對b₁=(1,1)、b₂=(1,−1)，φ₁=(x+y)/2、φ₂=(x−y)/2為雙基底。",
      "en": "For b1=(1,1),b2=(1,-1), phi1=(x+y)/2,phi2=(x-y)/2 form the dual basis."
    },
    "negative_controls": [
      {
        "claim": {
          "zh-Hant": "b₁與φ₁是同一典範物件。",
          "en": "b1 and phi1 are canonically the same object."
        },
        "expected": "reject",
        "reason": {
          "zh-Hant": "一個是向量，一個是V→R函數。",
          "en": "One is a vector, the other a function V to R."
        }
      },
      {
        "claim": {
          "zh-Hant": "φ₁(b₂)=1。",
          "en": "phi1(b2)=1."
        },
        "expected": "reject",
        "reason": {
          "zh-Hant": "(1+(−1))/2=0。",
          "en": "(1+(-1))/2=0."
        }
      },
      {
        "claim": {
          "zh-Hant": "covector換基也乘P^{-1}。",
          "en": "Covectors also multiply P inverse."
        },
        "expected": "reject",
        "reason": {
          "zh-Hant": "本例ℓ的B值為(4,2)，不是(2,1)。",
          "en": "Here ell's B-values are (4,2), not (2,1)."
        }
      }
    ],
    "status": "candidate",
    "gaps": [],
    "verification": {
      "structure": "checked_local_script",
      "mathematics": "candidate_argument",
      "formalization": "not_formalized"
    },
    "rule_glossary": [
      {
        "id": "calc",
        "kind": "prerequisite",
        "statement": {
          "zh-Hant": "假設通常實數域與座標向量運算、矩陣乘法、線性獨立及生成的定義；所用消去均為可逆初等列運算。",
          "en": "Assume the real field, usual coordinate-vector arithmetic, matrix multiplication, and definitions of independence and span; elimination uses invertible elementary row operations."
        }
      },
      {
        "id": "mko_definition",
        "kind": "cited",
        "statement": {
          "zh-Hant": "本輪限有限維V=R^n，以row covector給出線性泛函的symbolic全稱證書，並以phi_i(v_j)=delta_ij核dual basis。primal vector與dual functional不混同；沒有額外內積時不宣稱V與V*典範識別。",
          "en": "This slice uses finite-dimensional V=R^n. A row covector gives a symbolic linearity certificate, and a dual basis is checked by phi_i(v_j)=delta_ij. A primal vector and a dual functional are distinct; without extra structure no canonical identification V→V* is claimed."
        },
        "source": {
          "mko_id": "mko-dual-vector-space",
          "sha256": "1994bbbcc73dff239e5c7cfdaba60f5dc5aadb1a0a4603f613e4b1371d59234a",
          "commit": "b1b2f1dcf8c50d67a93fe52d95f8eef7b3abba9f"
        }
      }
    ],
    "revision_log": [],
    "numeric_checks": [
      {
        "id": "pair",
        "lhs": "(1-(-1))/2",
        "rhs": "1",
        "step": "S04"
      },
      {
        "id": "covector",
        "lhs": "3+1",
        "rhs": "4",
        "step": "S08"
      }
    ]
  },
  "presentation": {
    "md_scope": {
      "zh-Hant": "R²明示泛函、全稱線性及四個pairings；不作無額外結構的典範識別。",
      "en": "Explicit R2 functionals, universal linearity and four pairings; no canonical identification without extra structure."
    },
    "md_symbols": [
      [
        "V^*",
        "實線性對偶空間",
        "real linear dual"
      ],
      [
        "\\phi_i",
        "雙基底泛函",
        "dual-basis functional"
      ],
      [
        "P",
        "primal基底columns",
        "primal basis columns"
      ]
    ],
    "md_error_controls": [
      {
        "title": "四pairings / Four pairings",
        "zh": "逐對核全部δᵢⱼ，不只對角格。",
        "en": "Check all delta_ij pairings, not only diagonal entries."
      },
      {
        "title": "型別 / Types",
        "zh": "V*是函數空間，row座標需指定基底。",
        "en": "V* is a function space, and row coordinates require a chosen basis."
      }
    ],
    "md_open_items": []
  },
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    "bilingual_sync": "complete_source_bound",
    "formal_Lean": "NOT_RUN",
    "reader_review": "142_of_142_source_bound",
    "wording_review": "original_Lead_decisions_resolved",
    "glossary_reader_paraphrases": [],
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    "scope": "Owner-adopted reader revision. Lead and bilingual review concern the recorded text and premises; no new universal or Lean proof, canonical promotion or historical-label rewrite."
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}
