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# Edit detail for SandBox Aldor Category Theory 3 revision 7 of 7

 1 2 3 4 5 6 7 Editor: Bill Page Time: 2007/11/21 03:13:57 GMT-8 Note:

```changed:
-#library    lBasics  "basics.ao"
-import from lBasics
-
-#library    lCategories  "categories.ao"
-import from lCategories

#library   lBasics           "basics.ao"
#library   lCategories   "categories.ao"
import from lBasics,lCategories
```

aldor
```#include "axiom"
#pile
#library   lBasics           "basics.ao"
#library   lCategories   "categories.ao"
import from lBasics,lCategories
+++
+++  Slice Category
+++
Slice(Obj:Category,X:Obj):Category == with
slice: % -> X
SliceCategory(Obj:Category,X:Obj):Join(MathCategory Slice(Obj,X), Final Slice(Obj,X)) == add
One():Slice(Obj,X) ==
Rep == X; import from Rep
slice:%->X == (x:%):X +-> rep x
one(A:Slice(Obj,X)):(A->One()) == (a:A):One() +-> (slice a) pretend One()
+++
+++  CoSlice Category
+++
CoSlice(Obj:Category,X:Obj):Category == with
coslice: X -> %
CoSliceCategory(Obj:Category,X:Obj):Join(MathCategory CoSlice(Obj,X), Initial CoSlice(Obj,X)) == add
Zero():CoSlice(Obj,X) ==
Rep == X
coslice:X->% == (x:X):% +-> per x
zero(A:CoSlice(Obj,X)):(Zero()->A) == (z:Zero()):A +-> coslice (z pretend X)
+++
+++  The Category of Pairs with pairs of morphisms as morphisms
+++
Pair(Obj:Category):Category == with
product: % -> (Obj,Obj)
product:      (Obj,Obj) ->%
```   Compiling FriCAS source code from file