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User:Michiexile/MATH198/Lecture 5

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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.
 
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.
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===Limits and colimits===
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 +
* Generalizing these constructions
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* Diagram and universal object mapping to (from) the diagram
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* Express product/coproduct as limit/colimit
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* Issues with Haskell
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** No dependent types
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** No compiler-enforced equational conditions
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** Can be ''simulated'' but not enforced, e.g. using QuickCheck.
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====Useful limits and colimits====
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=====Equalizer, coequalizer=====
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* Kernels, cokernels, images, coimages
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** connect to linear algebra: null spaces et.c.
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=====Pushout and pullback squares=====
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* Computer science applications

Revision as of 01:41, 8 October 2009

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.


Contents

1 Limits and colimits

  • Generalizing these constructions
  • Diagram and universal object mapping to (from) the diagram
  • Express product/coproduct as limit/colimit
  • Issues with Haskell
    • No dependent types
    • No compiler-enforced equational conditions
    • Can be simulated but not enforced, e.g. using QuickCheck.

1.1 Useful limits and colimits

1.1.1 Equalizer, coequalizer
  • Kernels, cokernels, images, coimages
    • connect to linear algebra: null spaces et.c.
1.1.2 Pushout and pullback squares
  • Computer science applications