Esmaspäev, august 03, 2026

Ajalugu, Täna ajaloos

TÄNA AJALOOS, 11. juuli ⟩ Avati Tallinna teletorn

Elements

Rank-nullity theoremThe rank-nullity theorem states that for any linear map where is finite-dimensional, the dimension of equals the sum of the map's rank and nullity.[1][2][3]

Observations

  • One
  • Two
  • Three

Every linear injection has a left-inverse.

Every linear surjection has a right-inverse.

Commentary

There is hardly any theory which is more elementary [than linear algebra], in spite of the fact that generations of professors and textbook writers have obscured its simplicity by preposterous calculations with matrices.

We share a philosophy about linear algebra: we think basis-free, we write basis-free, but when the chips are down we close the office door and compute with matrices like fury.

— Irving Kaplansky, in writing about Paul Halmos

Citations

  1. ^ Axler (2015) p. 63, § 3.22
  2. ^ Katznelson & Katznelson (2008) p. 52, § 2.5.1
  3. ^ Valenza (1993) p. 71, § 4.3

Sources

Textbooks

  • Dummit, David S.; Foote, Richard M. (2004). Abstract Algebra (3rd ed.). Wiley. ISBN 978-0-471-43334-7.
  • Hefferon, Jim (2020). Linear Algebra (4th ed.). Orthogonal Publishing. ISBN 978-1-944325-11-4.
  • Strang, Gilbert (2016). Introduction to Linear Algebra (5th ed.). Wellesley Cambridge Press. ISBN 978-0-9802327-7-6.
  • Tao, Terence (2017) [2014]. Analysis 1 (3rd ed.). Hindustan Book Agency. ISBN 978-93-80250-64-9.
  • Tao, Terence (2017) [2014]. Analysis 2 (3rd ed.). Hindustan Book Agency. ISBN 978-93-80250-65-6.


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