bump mathlib
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@@ -36,6 +36,8 @@ lemma sum_const_add (n : ℕ) : (∑ i in Fin n, 0) = 0 := by
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Mit `simp?` anstatt `simp` kannst du zudem schauen, welche Lemmas von `simp` benutzt wurde.
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"
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open BigOperators
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Statement
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"Zeige dass $\\sum_{i = 0} ^ {n-1} (0 + 0) = 0$."
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(n : ℕ) : (∑ i : Fin n, (0 + 0)) = 0 := by
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@@ -25,6 +25,8 @@ vom Typ `Fin n`, das heisst, man muss diesen eigentlich immer mit `(i : ℕ)`
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als natürliche Zahl verwenden.
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"
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open BigOperators
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Statement
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"Zeige dass $\\sum_{i=0}^{n-1} (i + 1) = n + \\sum_{i=0}^{n-1} i$."
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(n : ℕ) : ∑ i : Fin n, ((i : ℕ) + 1) = n + (∑ i : Fin n, (i : ℕ)) := by
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@@ -29,6 +29,8 @@ Für den Induktionsschritt braucht man fast immer zwei technische Lemmas:
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-- Note: I don't want to deal with Nat-division, so I stated it as `2 * ... = ...` instead.
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open BigOperators
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Statement
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"Zeige $\\sum_{i = 0}^n i = \\frac{n \\cdot (n + 1)}{2}$."
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(n : ℕ) : 2 * (∑ i : Fin (n + 1), ↑i) = n * (n + 1) := by
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@@ -15,6 +15,8 @@ Introduction
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Hier nochmals eine Übung zur Induktion.
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"
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open BigOperators
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Statement
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"Zeige folgende Gleichung zur Summe aller ungeraden Zahlen:
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@@ -16,6 +16,7 @@ TODO: Induktion (& induktion vs rcases)
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"
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open BigOperators
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example (x : ℕ) (n : ℕ) : 1 + n * x ≤ (x + 1) ^ n := by
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induction' n with n hn
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@@ -33,10 +34,11 @@ example (n : ℕ) : (∑ i : Fin (n + 1), ↑(2 * i - 1)) = n ^ 2 := by
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Statement
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"Zeige $\\sum_{i = 0}^n i = \\frac{n ⬝ (n + 1)}{2}$."
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(n : ℕ) : (∑ i : Fin (n + 1), ↑i) = n * (n + 1) / 2 := by
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apply hh1
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induction' n with n hn
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simp
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sorry
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-- apply hh1
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-- induction' n with n hn
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-- simp
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-- sorry
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-- rw [Fin.sum_univ_castSucc]
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-- simp [nat_succ]
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-- rw [mul_add, hn]
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@@ -14,6 +14,7 @@ Introduction
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"
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"
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open BigOperators
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Statement
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"Zeige $\\sum_{i = 0}^n i^3 = (\\sum_{i = 0}^n i^3)^2$."
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