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Vector spaces

Learning tasks
    
Lesson
Text book
Exercises Correction
Conventions
Throughout this exercise sheet, unless otherwise stated, \(\mathbb{K}\) denotes either \(\mathbb{R}\) or \(\mathbb{C}\), \(E\) denotes a \(\mathbb{K}\)-vector space, and \(n, p\) are positive integers. The reference \(\mathbb{K}\)-vector spaces are \(\mathbb{K}^n\), \(M_{n,p}(\mathbb{K})\), \(\mathbb{K}[X]\), \(\mathbb{K}_n[X]\), \(\mathbb{K}^\Omega\) (functions from a set \(\Omega\) to \(\mathbb{K}\)), and \(\mathbb{K}^\mathbb{N}\) (sequences). The notation \(\mathrm{Vect}(X)\) denotes the subspace spanned by a part \(X\) of \(E\). The dimension theory (existence of a finite basis, dimension formula, theorem of the incomplete basis, rank) is deferred to the next chapter, Finite-dimensional vector spaces; this sheet stays in the dimension-free setting.
A) Vector spaces
    I) Definition and rules of calculation
      1) Recognizing a vector spaceEx 1 Ex 2 Ex 3
    II) Reference vector spaces
      2) Identifying reference spacesEx 4 Ex 5 Ex 6
    III) Linear combinations
      3) Computing linear combinationsEx 7 Ex 8 Ex 9
B) Subspaces
    I) Definition and characterization
      4) Identifying subspacesEx 10 Ex 11 Ex 12 Ex 13 Ex 14
    II) Reference subspaces
      5) Recognizing function subspacesEx 15 Ex 16 Ex 17 Ex 18
    III) Intersection of subspaces
      6) Computing intersectionsEx 19 Ex 20 Ex 21
    IV) Subspace spanned by a set
      7) Working with VectEx 22 Ex 23 Ex 24 Ex 25
C) Families of vectors
    I) Generating families
      8) Finding a generating familyEx 26 Ex 27 Ex 28
    II) Free and dependent families
      9) Showing a family is freeEx 29 Ex 30 Ex 31 Ex 32 Ex 33 Ex 34
    III) Bases and coordinates
      10) Identifying a basisEx 35 Ex 36 Ex 37
      11) Finding coordinatesEx 38 Ex 39 Ex 40
D) Sum of subspaces
    I) Sum of two subspaces
      12) Computing a sumEx 41 Ex 42 Ex 43 Ex 44
    II) Direct sum
      13) Recognizing a direct sumEx 45 Ex 46 Ex 47 Ex 48
    III) Supplementary subspaces
      14) Showing supplementaryEx 49 Ex 50 Ex 51 Ex 52
      15) Finding a supplementaryEx 53 Ex 54 Ex 55