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Edit detail for SandBoxMorphism revision 7 of 15

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Editor: Bill Page Time: 2008/06/18 17:35:45 GMT-7
Note: simpler Automorph

removed:
-      morphism: (R -> R, R -> R) -> %
-        ++ morphism(f, g) returns the invertible morphism given by f, where
-        ++ g is the inverse of f..

changed:
-      err:   R -> R
-      iter:  (R -> R, NonNegativeInteger, R) -> R
-      iterat: (R -> R, R -> R, Integer, R) -> R
-      apply: (%, R, Integer) -> R
      iter:  (R -> R, Integer, R) -> R

removed:
-      err r                           == error "Morphism is not invertible"

removed:
-      elt(f, r)                       == apply(f, r, 1)

changed:
-      morphism(f:R -> R):%            == morphism(f, err)
-      morphism(f, g)                  == iterat(f, g, #2, #1)
-      apply(f, r, n) == (g := f pretend ((R, Integer) -> R); g(r, n))
-
-      iterat(f, g, n, r) ==
-          n < 0 => iter(g, (-n)::NonNegativeInteger, r)
-          iter(f, n::NonNegativeInteger, r)
      morphism(f)                  ==    iter(f, #2, #1)
      elt(f, r) == (g := f pretend ((R, Integer) -> R); g(r, 1))

spad)abbrev domain MORPH Morphism
T ==> SetCategory
Morphism(source:T, target:T): with
  domain:%->T
  codomain:%->T
  coerce:(source->target)  -> %
  coerce:%->(source->target)
  coerce:%->OutputForm
  --elt:(%,source)->target
 == (source->target) add
  Rep == (source->target)
  domain(p:%):T == source
  codomain(p:%):T == target
  coerce(r:(source->target)):% == per(r)
  coerce(p:%):(source->target) == p pretend (source->target)
  coerce(p:%):OutputForm == p pretend OutputForm
  --elt(f,x) == (f::(source->target))(x)

spad

   Compiling OpenAxiom source code from file 
      /var/zope2/var/LatexWiki/2396666756253990559-25px001.spad using 
      Spad compiler.
   MORPH abbreviates domain Morphism 
   processing macro definition T$ ==> SetCategory 
------------------------------------------------------------------------
   initializing NRLIB MORPH for Morphism 
   compiling into NRLIB MORPH 
   Adding $ modemaps
   Adding source modemaps
   Adding target modemaps
   Parameters of  rep  are of wrong type:
    G1393 must have type source not $
   compiling local rep : source -> source -> target
      MORPH;rep is replaced by G1393 
Time: 0.01 SEC.
   compiling local per : source -> target -> %
      MORPH;per is replaced by G1393 
Time: 0 SEC.
   compiling exported domain : % -> SetCategory
Time: 0 SEC.
   compiling exported codomain : % -> SetCategory
Time: 0 SEC.
   compiling exported coerce : source -> target -> %
Time: 0 SEC.
   compiling exported coerce : % -> source -> target
      MORPH;coerce;$M;6 is replaced by p 
Time: 0 SEC.
   Adding OutputForm modemaps
   compiling exported coerce : % -> OutputForm
      MORPH;coerce;$Of;7 is replaced by p 
Time: 0 SEC.
(time taken in buildFunctor:  0)
;;;     ***       |Morphism| REDEFINED
;;;     ***       |Morphism| REDEFINED
Time: 0 SEC.
   Cumulative Statistics for Constructor Morphism
      Time: 0.01 seconds
--------------non extending category----------------------
   Morphism(#1,#2) of category CATEGORY(domain,domain: % -> 
      SetCategory,codomain: % -> SetCategory,coerce: (#1 -> #2) -> %,
      coerce: % -> (#1 -> #2),coerce: % -> OutputForm)
    has no NIL
   finalizing NRLIB MORPH 
   Processing Morphism for Browser database:
--->-->Morphism((domain (T$ %))): Not documented!!!!
--->-->Morphism((codomain (T$ %))): Not documented!!!!
--->-->Morphism((coerce (% (Mapping target source)))): Not documented!!!!
--->-->Morphism((coerce ((Mapping target source) %))): Not documented!!!!
--->-->Morphism((coerce ((OutputForm) %))): Not documented!!!!
--->-->Morphism(constructor): Not documented!!!!
--->-->Morphism(): Missing Description
------------------------------------------------------------------------
   Morphism is now explicitly exposed in frame initial 
   Morphism will be automatically loaded when needed from 
      /var/zope2/var/LatexWiki/MORPH.NRLIB/code.o

If we define elt (commented out above), then f(1.1) gives the following:

  Error: Caught fatal error [memory may be damaged]
  Fast links are on: do (si::use-fast-links nil) for debugging
  Error signalled by RETURN.
  Broken at APPLY.  Type :H for Help.
  BOOT>>
  Error: The variable QUIT is unbound.
  Fast links are on: do (si::use-fast-links nil) for debugging
  Error signalled by EVALHOOK.
  Backtrace: system:universal-error-handler > evalhook > lambda > lambda-closure > block > apply > APPLY

But the same coercion works in the interpreter.

axiom)show Morphism(Float,Integer)
 Morphism(Float,Integer) is a domain constructor.
 Abbreviation for Morphism is MORPH
 This constructor is exposed in this frame.
 Issue )edit /var/zope2/var/LatexWiki/2396666756253990559-25px001.spad to see algebra source
code for MORPH
------------------------------- Operations --------------------------------
 codomain : % -> SetCategory           coerce : % -> (Float -> Integer)
 coerce : % -> OutputForm              coerce : (Float -> Integer) -> %
 domain : % -> SetCategory
f:Morphism(Float,Integer)

Type: Void

axiomf:=(x:Float):Integer +->wholePart(x)
; (DEFUN |*1;anonymousFunction;0;initial;internal| ...) is being compiled.
;; The variable |*1;anonymousFunction;0;initial;internal;MV| is undefined.
;; The compiler will assume this variable is a global.

(1)

Type: Morphism(Float,Integer)

axiomf(1.1)
   There are no library operations named f
      Use HyperDoc Browse or issue
                                 )what op f
      to learn if there is any operation containing " f " in its name.
   Cannot find a definition or applicable library operation named f
      with argument type(s)
                                    Float
      Perhaps you should use "@" to indicate the required return type,
      or "$" to specify which version of the function you need.
(f::(Float->Integer))(1.1)

(2)

Type: PositiveInteger?

axiom
domain f

(3)

Type: SetCategory?

axiom
codomain f

(4)

Type: SetCategory?

axiom
(f::(domain(f)->codomain(f)))(1.1)

(5)

Type: PositiveInteger?

Next let's study how this sort of thing is accomplished in a similar domain.

spad)abbrev domain AUTOM Automorph
++ Based on Automorphism by: Manuel Bronstein
++ Description:
++       Automorph R is the domain of automorphisms of R.
Automorph(R:Ring): Join(SetCategory, Eltable(R, R)) with
      morphism: (R -> R) -> %
        ++ morphism(f) returns the non-invertible morphism given by f.
   == add
      iter:  (R -> R, Integer, R) -> R
      Rep := ((R, Integer) -> R)
      f = g                           == EQ(f, g)$Lisp
      coerce(f:%):OutputForm          == message("S -> S")
      morphism(f)                  ==    iter(f, #2, #1)
      elt(f, r) == (g := f pretend ((R, Integer) -> R); g(r, 1))
      iter(f, n, r) ==
          for i in 1..n repeat r := f r
          r

spad

   Compiling OpenAxiom source code from file 
      /var/zope2/var/LatexWiki/1485257945853614386-25px003.spad using 
      Spad compiler.
   AUTOM abbreviates domain Automorph 
------------------------------------------------------------------------
   initializing NRLIB AUTOM for Automorph 
   compiling into NRLIB AUTOM 
   Adding $ modemaps
   Adding R modemaps
   Adding Boolean modemaps
   compiling exported = : (%,%) -> Boolean
      AUTOM;=;2$B;1 is replaced by EQ 
Time: 0 SEC.
   Adding OutputForm modemaps
   compiling exported coerce : % -> OutputForm
   Adding String modemaps
Time: 0.01 SEC.
   compiling exported morphism : R -> R -> %
   Adding Integer modemaps
Time: 0.06 SEC.
   compiling exported elt : (%,R) -> R
   Adding Integer modemaps
Time: 0 SEC.
   Adding Integer modemaps
   compiling local iter : (R -> R,Integer,R) -> R
   Adding SingleInteger modemaps
   Adding NonNegativeInteger modemaps
Time: 0.01 SEC.
(time taken in buildFunctor:  0)
;;;     ***       |Automorph| REDEFINED
;;;     ***       |Automorph| REDEFINED
Time: 0 SEC.
   Cumulative Statistics for Constructor Automorph
      Time: 0.08 seconds
   finalizing NRLIB AUTOM 
   Processing Automorph for Browser database:
     -- morphism : (R -> R) -> %
     -- constructor
------------------------------------------------------------------------
   Automorph is now explicitly exposed in frame initial 
   Automorph will be automatically loaded when needed from 
      /var/zope2/var/LatexWiki/AUTOM.NRLIB/code.o

axiomp:=morphism((x:Integer):Integer +-> x+1)$Automorph(Integer)
; (DEFUN |*1;anonymousFunction;1;initial;internal| ...) is being compiled.
;; The variable |*1;anonymousFunction;1;initial;internal;MV| is undefined.
;; The compiler will assume this variable is a global.

(6)

Type: Automorph Integer

axiom
p(2)

(7)

Type: PositiveInteger?