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authordos-reis <gdr@axiomatics.org>2010-06-12 11:42:58 +0000
committerdos-reis <gdr@axiomatics.org>2010-06-12 11:42:58 +0000
commit22e30ed358890e963a5777f0f6c843fba4f841e4 (patch)
treebccaf9422e96445dfa1bc74ae65e770c79971e84 /src/algebra/perm.spad.pamphlet
parentfecb6dc501ce3eeadb6d3f5a39de6a1ac808190d (diff)
downloadopen-axiom-22e30ed358890e963a5777f0f6c843fba4f841e4.tar.gz
* algebra/permgrps.spad.pamphlet (PermutationGroup): Rename
movedPoints to support. Adjust call eval. * algebra/perm.spad.pamphlet (PermutationCategory): Now extend Eltable. Remove eval. Rename movedPoints to support. (Permutation): Adjust. * algebra/irsn.spad.pamphlet (listPermutationIrrRepSymNatPackage): Change call to eval to elt. * algebra/rep1.spad.pamphlet: Likewise.
Diffstat (limited to 'src/algebra/perm.spad.pamphlet')
-rw-r--r--src/algebra/perm.spad.pamphlet36
1 files changed, 15 insertions, 21 deletions
diff --git a/src/algebra/perm.spad.pamphlet b/src/algebra/perm.spad.pamphlet
index 69f33f83..2dd9da5b 100644
--- a/src/algebra/perm.spad.pamphlet
+++ b/src/algebra/perm.spad.pamphlet
@@ -15,7 +15,7 @@
++ Authors: Holger Gollan, Johannes Grabmeier, Gerhard Schneider
++ Date Created: 27 July 1989
++ Date Last Updated: 29 March 1990
-++ Basic Operations: cycle, cycles, eval, orbit
+++ Basic Operations: cycle, cycles, orbit
++ Related Constructors: PermutationGroup, PermutationGroupExamples
++ Also See: RepresentationTheoryPackage1
++ AMS Classifications:
@@ -24,7 +24,8 @@
++ Description: PermutationCategory provides a categorial environment
++ for subgroups of bijections of a set (i.e. permutations)
-PermutationCategory(S:SetCategory): Category == Group with
+PermutationCategory(S:SetCategory): Category ==
+ Join(Group,Eltable(S,S)) with
cycle : List S -> %
++ cycle(ls) coerces a cycle {\em ls}, i.e. a list with not
++ repetitions to a permutation, which maps {\em ls.i} to
@@ -37,12 +38,9 @@ PermutationCategory(S:SetCategory): Category == Group with
++ {\em ls.i} to {\em ls.i+1}, indices modulo the length of the list,
++ then these permutations are mutiplied.
++ Error: if repetitions occur in one cycle.
- eval : (%,S) -> S
- ++ eval(p, el) returns the image of {\em el} under the
- ++ permutation p.
- elt : (%,S) -> S
- ++ elt(p, el) returns the image of {\em el} under the
- ++ permutation p.
+ support: % -> Set S
+ ++ \spad{support p} returns the set of points not fixed by the
+ ++ permutation \spad{p}.
orbit : (%,S) -> Set S
++ orbit(p, el) returns the orbit of {\em el} under the
++ permutation p, i.e. the set which is given by applications of
@@ -61,7 +59,7 @@ PermutationCategory(S:SetCategory): Category == Group with
++ Authors: Johannes Grabmeier, Holger Gollan
++ Date Created: 19 May 1989
++ Date Last Updated: 2 June 2006
-++ Basic Operations: _*, degree, movedPoints, cyclePartition, order,
+++ Basic Operations: _*, degree, support, cyclePartition, order,
++ numberOfCycles, sign, even?, odd?
++ Related Constructors: PermutationGroup, PermutationGroupExamples
++ Also See: RepresentationTheoryPackage1
@@ -126,8 +124,6 @@ Permutation(S:SetCategory): public == private where
degree : % -> NonNegativeInteger
++ degree(p) retuns the number of points moved by the
++ permutation p.
- movedPoints : % -> Set S
- ++ movedPoints(p) returns the set of points moved by the permutation p.
cyclePartition : % -> Partition
++ cyclePartition(p) returns the cycle structure of a permutation
++ p including cycles of length 1 only if S is finite.
@@ -300,7 +296,7 @@ Note that before [[patch--50]] this read
coercePreimagesImages preImageAndImage ==
p : % := [preImageAndImage.1,preImageAndImage.2]
\end{verbatim}
-causing bugs when computing [[movedPoints]], [[fixedPoints]], [[even?]],
+causing bugs when computing [[support]], [[fixedPoints]], [[even?]],
[[odd?]], etc., as reported in Issue~\#295.
The other coercion facilities check for fixed points. It also seems that [[*]]
@@ -308,7 +304,7 @@ removes fixed points from its result.
<<TEST PERM>>=
p := coercePreimagesImages([[1,2,3],[1,2,3]])
- movedPoints p -- should return {}
+ support p -- should return {}
even? p -- should return true
p := coercePreimagesImages([[0,1,2,3],[3,0,2,1]])$PERM ZMOD 4
fixedPoints p -- should return {2}
@@ -319,9 +315,9 @@ removes fixed points from its result.
<<domain PERM Permutation>>=
- movedPoints p == construct p.1
+ support p == construct p.1
- degree p == #movedPoints p
+ degree p == #support p
p = q ==
#(preimp := p.1) ~= #(preimq := q.1) => false
@@ -334,12 +330,12 @@ removes fixed points from its result.
orbit(p ,el) ==
-- start with a 1-element list:
out : Set S := brace list el
- el2 := eval(p, el)
+ el2 := p(el)
while el2 ~= el repeat
-- be carefull: insert adds one element
-- as side effect to out
insert!(el2, out)
- el2 := eval(p, el2)
+ el2 := p(el2)
out
cyclePartition p ==
@@ -450,13 +446,11 @@ removes fixed points from its result.
inv p == [p.2, p.1]
- eval(p, el) ==
+ elt(p,el) ==
pos := position(el, p.1)
pos = 0 => el
(p.2).pos
- elt(p, el) == eval(p, el)
-
numberOfCycles p == #coerceToCycle(p, false)
@@ -480,7 +474,7 @@ Up to [[patch--50]] we did not check for duplicates.
Up to [[patch--50]] we did not check for duplicates.
<<domain PERM Permutation>>=
- fixedPoints ( p ) == complement movedPoints p
+ fixedPoints ( p ) == complement support p
cyclePartition p ==
pt := partition([#c::PI for c in coerceToCycle(p, false)])$Partition