diff --git a/Math2001/Homework/hw10.lean b/Math2001/Homework/hw10.lean new file mode 100644 index 00000000..2bbb74cb --- /dev/null +++ b/Math2001/Homework/hw10.lean @@ -0,0 +1,158 @@ +/- Copyright (c) Heather Macbeth, 2023-4. All rights reserved. -/ +import Mathlib.Data.Real.Basic +import Library.Basic +import Library.Tactic.ModEq +import AutograderLib + +math2001_init +set_option quotPrecheck false + + +/-! # Homework 10 + +Don't forget to compare with the text version, +https://github.com/hrmacbeth/math2001/wiki/Homework-10, +for clearer statements and any special instructions. -/ + + +/- Problem 1: prove one of these, delete the other -/ + +@[autograded 4] +theorem problem1a : { m : ℤ | m ≥ 10 } ⊆ { n : ℤ | n ^ 3 - 6 * n ^ 2 ≥ 4 * n } := by + sorry + +@[autograded 4] +theorem problem1b : { m : ℤ | m ≥ 10 } ⊈ { n : ℤ | n ^ 3 - 6 * n ^ 2 ≥ 4 * n } := by + sorry + + +/- Problem 2: prove one of these, delete the other -/ + +@[autograded 3] +theorem problem2a : { t : ℝ | t ^ 2 - 3 * t + 2 = 0 } = { s : ℝ | s = 2 } := by + sorry + +@[autograded 3] +theorem problem2b : { t : ℝ | t ^ 2 - 3 * t + 2 = 0 } ≠ { s : ℝ | s = 2 } := by + sorry + + +/- Problem 3: prove one of these, delete the other -/ + +@[autograded 3] +theorem problem3a : {1, 2, 3} ∩ {2, 3, 4} ⊆ {2, 3, 6} := by + sorry + + +@[autograded 3] +theorem problem3b : {1, 2, 3} ∩ {2, 3, 4} ≠ {2, 3, 6} := by + sorry + + +/- Problem 4 -/ + +@[autograded 4] +theorem problem4 : { r : ℤ | r ≡ 11 [ZMOD 15] } + = { s : ℤ | s ≡ 2 [ZMOD 3] } ∩ { t : ℤ | t ≡ 1 [ZMOD 5] } := by + sorry + + + +/-! ### Problem 5 starts here -/ + + +local infix:50 "∼" => fun (a b : ℤ) ↦ ∃ m n, m > 0 ∧ n > 0 ∧ a * m = b * n + + +/- Problem 5.1: prove one of these, delete the other -/ + +@[autograded 2] +theorem problem51a : Reflexive (· ∼ ·) := by + sorry + +@[autograded 2] +theorem problem51b : ¬ Reflexive (· ∼ ·) := by + sorry + + +/- Problem 5.2: prove one of these, delete the other -/ + +@[autograded 2] +theorem problem52a : Symmetric (· ∼ ·) := by + sorry + +@[autograded 2] +theorem problem52b : ¬ Symmetric (· ∼ ·) := by + sorry + + +/- Problem 5.3: prove one of these, delete the other -/ + +@[autograded 2] +theorem problem53a : AntiSymmetric (· ∼ ·) := by + sorry + +@[autograded 2] +theorem problem53b : ¬ AntiSymmetric (· ∼ ·) := by + sorry + + +/- Problem 5.4: prove one of these, delete the other -/ + +@[autograded 2] +theorem problem54a : Transitive (· ∼ ·) := by + sorry + +@[autograded 2] +theorem problem54b : ¬ Transitive (· ∼ ·) := by + sorry + + + +/-! ### Problem 6 starts here -/ + +infix:50 "≺" => fun ((x1, y1) : ℝ × ℝ) (x2, y2) ↦ (x1 ≤ x2 ∧ y1 ≤ y2) + + +/- Problem 6.1: prove one of these, delete the other -/ + +@[autograded 2] +theorem problem61a : Reflexive (· ≺ ·) := by + sorry + +@[autograded 2] +theorem problem61b : ¬ Reflexive (· ≺ ·) := by + sorry + + +/- Problem 6.2: prove one of these, delete the other -/ + +@[autograded 2] +theorem problem62a : Symmetric (· ≺ ·) := by + sorry + +@[autograded 2] +theorem problem62b : ¬ Symmetric (· ≺ ·) := by + sorry + + +/- Problem 6.3: prove one of these, delete the other -/ + +@[autograded 2] +theorem problem63a : AntiSymmetric (· ≺ ·) := by + sorry + +@[autograded 2] +theorem problem63b : ¬ AntiSymmetric (· ≺ ·) := by + sorry + + +/- Problem 6.4: prove one of these, delete the other -/ + +@[autograded 2] +theorem problem64a : Transitive (· ≺ ·) := by + sorry + +@[autograded 2] +theorem problem64b : ¬ Transitive (· ≺ ·) := by + sorry