{"schema_version":"ocme-site-results-v1","locale":"en","page_type":"derivations","facts":{"questions":36000,"reviewed":36000,"display_candidates":0,"knowledge":302,"guides":299,"paths":59,"batches":360,"families":1441,"atlas":302,"core":80,"evidence":9,"formal_evidence":5,"formal_subjects":4,"lean_files":6,"lean_toolchain":"leanprover/lean4:v4.30.0","question_state":"candidate","english_state":"ai_candidate","question_Lean":"NOT_RUN","canonical_truth_promotion":false},"filters":{"q":"mko-real-inner-product-space"},"kind":"guides","total":1,"pages":1,"page":1,"entries":[{"id":"derivation-mko-real-inner-product-space-01","title":{"zh-Hant":"實內積空間：以 Sylvester 條件為 ℝ² 上的矩陣形式作全稱正定證書","en":"Real inner-product space: Sylvester conditions as a universal positive-definiteness certificate for a matrix form on ℝ²"},"summary":{"zh-Hant":"設 M 為第一行 (2,1)、第二行 (1,3) 的整數對稱矩陣，⟨x,y⟩_M=xᵀMy（x,y∈ℝ²）。（一）分別證明 ⟨·,·⟩_M 雙線性、對稱、正定，所以是 ℝ² 上的內積；正定性以 2×2 Sylvester 條件（完整證明其充分與必要方向）作全稱證書。（二）判定 N（行 (1,2),(2,1)）、P（行 (1,1),(1,1)）、R（行 (2,1),(0,3)）給出的形式為何不是內積。","en":"Let M be the symmetric integer matrix with first row (2,1) and second row (1,3), and ⟨x,y⟩_M=xᵀMy for x,y∈ℝ². (1) Prove separately that ⟨·,·⟩_M is bilinear, symmetric and positive definite, hence an inner product on ℝ²; positive definiteness is certified universally by the 2-by-2 Sylvester conditions, with both sufficiency and necessity proved in full. (2) Decide why the forms given by N (rows (1,2),(2,1)), P (rows (1,1),(1,1)) and R (rows (2,1),(0,3)) are not inner products."},"mko_ids":["mko-real-inner-product-space"]}],"title":"Concept derivation guides"}