User:Michiexile/MATH198/Lecture 7

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IMPORTANT NOTE: THESE NOTES ARE STILL UNDER DEVELOPMENT. PLEASE WAIT UNTIL AFTER THE LECTURE WITH HANDING ANYTHING IN, OR TREATING THE NOTES AS READY TO READ.

Some adjunctions we already know

  • initial/terminal are adjunctions.
  • (co)-products are adjunctions.
  • Actually, all (co)limits are adjunctions.


Some adjunctions we don't know yet

  • Existential and universal qualifiers as adjunctions.
  • Powersets and im(f) -| f^\inv

Properties of adjoints

RAPL: Right Adjoints Preserve Limits

Recognizing adjoints

Theorem (Freyd: The Adjoint Functor Theorem)


Why should we care in CS?

Monads