\documentclass{article} \usepackage{axiom} \begin{document} \title{src/algebra xpoly.spad} \author{Michel Petitot} \maketitle \begin{abstract} \end{abstract} \tableofcontents \eject \section{domain OFMONOID OrderedFreeMonoid} <>= import OrderedSet import OrderedMonoid import RetractableTo )abbrev domain OFMONOID OrderedFreeMonoid ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ The free monoid on a set \spad{S} is the monoid of finite products of ++ the form \spad{reduce(*,[si ** ni])} where the si's are in S, and the ni's ++ are non-negative integers. The multiplication is not commutative. ++ For two elements \spad{x} and \spad{y} the relation \spad{x < y} ++ holds if either \spad{length(x) < length(y)} holds or if these lengths ++ are equal and if \spad{x} is smaller than \spad{y} w.r.t. the lexicographical ++ ordering induced by \spad{S}. ++ This domain inherits implementation from \spadtype{FreeMonoid}. ++ Author: Michel Petitot (petitot@lifl.fr) OrderedFreeMonoid(S: OrderedSet): OFMcategory == OFMdefinition where NNI ==> NonNegativeInteger REC ==> Record(gen:S, exp:NNI) OFMcategory == Join(FreeMonoidCategory S,OrderedSet) with first: % -> S ++ \spad{first(x)} returns the first letter of \spad{x}. rest: % -> % ++ \spad{rest(x)} returns \spad{x} except the first letter. mirror: % -> % ++ \spad{mirror(x)} returns the reversed word of \spad{x}. lexico: (%,%) -> Boolean ++ \spad{lexico(x,y)} returns \spad{true} iff \spad{x} is smaller than \spad{y} ++ w.r.t. the pure lexicographical ordering induced by \spad{S}. lquo: (%, S) -> Union(%, "failed") ++ \spad{lquo(x, s)} returns the exact left quotient of \spad{x} ++ by \spad{s}. rquo: (%, S) -> Union(%, "failed") ++ \spad{rquo(x, s)} returns the exact right quotient ++ of \spad{x} by \spad{s}. div: (%, %) -> Union(Record(lm: %, rm: %), "failed") ++ \spad{x div y} returns the left and right exact quotients of ++ \spad{x} by \spad{y}, that is \spad{[l, r]} such that \spad{x = l * y * r}. ++ "failed" is returned iff \spad{x} is not of the form \spad{l * y * r}. ++ monomial of \spad{x}. length: % -> NNI ++ \spad{length(x)} returns the length of \spad{x}. varList: % -> List S ++ \spad{varList(x)} returns the list of variables of \spad{x}. OFMdefinition == FreeMonoid(S) add Rep := ListMonoidOps(S, NNI, 1) -- definitions lquo(w:%, l:S) == x: List REC := listOfMonoms(w)$Rep null x => "failed" fx: REC := first x fx.gen ~= l => "failed" fx.exp = 1 => makeMulti rest(x) makeMulti [[fx.gen, (fx.exp - 1)::NNI ]$REC, :rest x] rquo(w:%, l:S) == u:% := reverse w (r := lquo (u,l)) case "failed" => "failed" reverse! (r::%) length x == reduce("+" ,[f.exp for f in listOfMonoms x], 0) varList x == le: List S := [t.gen for t in listOfMonoms x] sort! removeDuplicates(le) first w == x: List REC := listOfMonoms w null x => error "empty word !!!" x.first.gen rest w == x: List REC := listOfMonoms w null x => error "empty word !!!" fx: REC := first x fx.exp = 1 => makeMulti rest x makeMulti [[fx.gen , (fx.exp - 1)::NNI ]$REC , :rest x] lexico(a,b) == -- ordre lexicographique la := listOfMonoms a lb := listOfMonoms b while (not null la) and (not null lb) repeat la.first.gen > lb.first.gen => return false la.first.gen < lb.first.gen => return true if la.first.exp = lb.first.exp then la:=rest la lb:=rest lb else if la.first.exp > lb.first.exp then la:=concat([la.first.gen, (la.first.exp - lb.first.exp)::NNI], rest lb) lb:=rest lb else lb:=concat([lb.first.gen, (lb.first.exp-la.first.exp)::NNI], rest la) la:=rest la empty? la and not empty? lb a < b == -- ordre lexicographique par longueur la:NNI := length a; lb:NNI := length b la = lb => lexico(a,b) la < lb mirror x == reverse(x)$Rep @ \section{category FMCAT FreeModuleCat} <>= import Ring import SetCategory import BiModule import RetractableTo )abbrev category FMCAT FreeModuleCat ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ A domain of this category ++ implements formal linear combinations ++ of elements from a domain \spad{Basis} with coefficients ++ in a domain \spad{R}. The domain \spad{Basis} needs only ++ to belong to the category \spadtype{SetCategory} and \spad{R} ++ to the category \spadtype{Ring}. Thus the coefficient ring ++ may be non-commutative. ++ See the \spadtype{XDistributedPolynomial} constructor ++ for examples of domains built with the \spadtype{FreeModuleCat} ++ category constructor. ++ Author: Michel Petitot (petitot@lifl.fr) FreeModuleCat(R, Basis):Category == Exports where R: Ring Basis: SetCategory TERM ==> Record(k: Basis, c: R) Exports == Join(BiModule(R,R), RetractableTo Basis) with * : (R, Basis) -> % ++ \spad{r*b} returns the product of \spad{r} by \spad{b}. coefficient : (%, Basis) -> R ++ \spad{coefficient(x,b)} returns the coefficient ++ of \spad{b} in \spad{x}. map : (R -> R, %) -> % ++ \spad{map(fn,u)} maps function \spad{fn} onto the coefficients ++ of the non-zero monomials of \spad{u}. monom : (Basis, R) -> % ++ \spad{monom(b,r)} returns the element with the single monomial ++ \spad{b} and coefficient \spad{r}. monomial? : % -> Boolean ++ \spad{monomial?(x)} returns true if \spad{x} contains a single ++ monomial. ListOfTerms : % -> List TERM ++ \spad{ListOfTerms(x)} returns a list \spad{lt} of terms with type ++ \spad{Record(k: Basis, c: R)} such that \spad{x} equals ++ \spad{reduce(+, map(x +-> monom(x.k, x.c), lt))}. coefficients : % -> List R ++ \spad{coefficients(x)} returns the list of coefficients of \spad{x}. monomials : % -> List % ++ \spad{monomials(x)} returns the list of \spad{r_i*b_i} ++ whose sum is \spad{x}. numberOfMonomials : % -> NonNegativeInteger ++ \spad{numberOfMonomials(x)} returns the number of monomials of \spad{x}. leadingMonomial : % -> Basis ++ \spad{leadingMonomial(x)} returns the first element from \spad{Basis} ++ which appears in \spad{ListOfTerms(x)}. leadingCoefficient : % -> R ++ \spad{leadingCoefficient(x)} returns the first coefficient ++ which appears in \spad{ListOfTerms(x)}. leadingTerm : % -> TERM ++ \spad{leadingTerm(x)} returns the first term which ++ appears in \spad{ListOfTerms(x)}. reductum : % -> % ++ \spad{reductum(x)} returns \spad{x} minus its leading term. -- attributs if R has CommutativeRing then Module(R) @ \section{domain FM1 FreeModule1} <>= import Ring import OrderedSet )abbrev domain FM1 FreeModule1 ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ This domain implements linear combinations ++ of elements from the domain \spad{S} with coefficients ++ in the domain \spad{R} where \spad{S} is an ordered set ++ and \spad{R} is a ring (which may be non-commutative). ++ This domain is used by domains of non-commutative algebra such as: ++ \spadtype{XDistributedPolynomial}, ++ \spadtype{XRecursivePolynomial}. ++ Author: Michel Petitot (petitot@lifl.fr) FreeModule1(R:Ring,S:OrderedSet): FMcat == FMdef where EX ==> OutputForm TERM ==> Record(k:S,c:R) FMcat == FreeModuleCat(R,S) with *:(S,R) -> % ++ \spad{s*r} returns the product \spad{r*s} ++ used by \spadtype{XRecursivePolynomial} FMdef == FreeModule(R,S) add -- representation Rep := List TERM -- declarations lt: List TERM x : % r : R s : S -- define numberOfMonomials p == # (p::Rep) ListOfTerms(x) == x:List TERM leadingTerm x == x.first leadingMonomial x == x.first.k coefficients x == [t.c for t in x] monomials x == [ monom (t.k, t.c) for t in x] retractIfCan x == numberOfMonomials(x) ~= 1 => "failed" x.first.c = 1 => x.first.k "failed" coerce(s:S):% == [[s,1$R]] retract x == (rr := retractIfCan x) case "failed" => error "FM1.retract impossible" rr :: S if R has noZeroDivisors then r * x == r = 0 => 0 [[u.k,r * u.c]$TERM for u in x] x * r == r = 0 => 0 [[u.k,u.c * r]$TERM for u in x] else r * x == r = 0 => 0 [[u.k,a] for u in x | not (a:=r*u.c)= 0$R] x * r == r = 0 => 0 [[u.k,a] for u in x | not (a:=u.c*r)= 0$R] r * s == r = 0 => 0 [[s,r]$TERM] s * r == r = 0 => 0 [[s,r]$TERM] monom(b,r):% == [[b,r]$TERM] outTerm(r:R, s:S):EX == r=1 => s::EX r::EX * s::EX coerce(a:%):EX == empty? a => (0$R)::EX reduce(_+, reverse! [outTerm(t.c, t.k) for t in a])$List(EX) coefficient(x,s) == null x => 0$R x.first.k > s => coefficient(rest x,s) x.first.k = s => x.first.c 0$R @ \section{category XALG XAlgebra} <>= import Ring import BiModule import CommutativeRing import Algebra )abbrev category XALG XAlgebra ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ This is the category of algebras over non-commutative rings. ++ It is used by constructors of non-commutative algebras such as: ++ \spadtype{XPolynomialRing}. ++ \spadtype{XFreeAlgebra} ++ Author: Michel Petitot (petitot@lifl.fr) XAlgebra(R: Ring): Category == Join(Ring, BiModule(R,R),CoercibleFrom R) with -- attributs if R has CommutativeRing then Algebra(R) -- if R has CommutativeRing then Module(R) -- add -- coerce(x:R):% == x * 1$% @ \section{category XFALG XFreeAlgebra} <>= import OrderedSet import Ring import XAlgebra import RetractableTo )abbrev category XFALG XFreeAlgebra ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ This category specifies opeations for polynomials ++ and formal series with non-commutative variables. ++ Author: Michel Petitot (petitot@lifl.fr) XFreeAlgebra(vl:OrderedSet,R:Ring):Category == Catdef where WORD ==> OrderedFreeMonoid(vl) -- monoide libre NNI ==> NonNegativeInteger I ==> Integer TERM ==> Record(k: WORD, c: R) Catdef == Join(Ring, XAlgebra(R), RetractableTo WORD) with *: (vl,%) -> % ++ \spad{v * x} returns the product of a variable \spad{x} by \spad{x}. *: (%, R) -> % ++ \spad{x * r} returns the product of \spad{x} by \spad{r}. ++ Usefull if \spad{R} is a non-commutative Ring. mindeg: % -> WORD ++ \spad{mindeg(x)} returns the little word which appears in \spad{x}. ++ Error if \spad{x=0}. mindegTerm: % -> TERM ++ \spad{mindegTerm(x)} returns the term whose word is \spad{mindeg(x)}. coef : (%,WORD) -> R ++ \spad{coef(x,w)} returns the coefficient of the word \spad{w} in \spad{x}. coef : (%,%) -> R ++ \spad{coef(x,y)} returns scalar product of \spad{x} by \spad{y}, ++ the set of words being regarded as an orthogonal basis. lquo : (%,vl) -> % ++ \spad{lquo(x,v)} returns the left simplification of \spad{x} by the variable \spad{v}. lquo : (%,WORD) -> % ++ \spad{lquo(x,w)} returns the left simplification of \spad{x} by the word \spad{w}. lquo : (%,%) -> % ++ \spad{lquo(x,y)} returns the left simplification of \spad{x} by \spad{y}. rquo : (%,vl) -> % ++ \spad{rquo(x,v)} returns the right simplification of \spad{x} by the variable \spad{v}. rquo : (%,WORD) -> % ++ \spad{rquo(x,w)} returns the right simplification of \spad{x} by \spad{w}. rquo : (%,%) -> % ++ \spad{rquo(x,y)} returns the right simplification of \spad{x} by \spad{y}. monom : (WORD , R) -> % ++ \spad{monom(w,r)} returns the product of the word \spad{w} by the coefficient \spad{r}. monomial? : % -> Boolean ++ \spad{monomial?(x)} returns true if \spad{x} is a monomial mirror: % -> % ++ \spad{mirror(x)} returns \spad{Sum(r_i mirror(w_i))} if \spad{x} writes \spad{Sum(r_i w_i)}. coerce : vl -> % ++ \spad{coerce(v)} returns \spad{v}. constant?:% -> Boolean ++ \spad{constant?(x)} returns true if \spad{x} is constant. constant: % -> R ++ \spad{constant(x)} returns the constant term of \spad{x}. quasiRegular? : % -> Boolean ++ \spad{quasiRegular?(x)} return true if \spad{constant(x)} is zero. quasiRegular : % -> % ++ \spad{quasiRegular(x)} return \spad{x} minus its constant term. if R has CommutativeRing then sh :(%,%) -> % ++ \spad{sh(x,y)} returns the shuffle-product of \spad{x} by \spad{y}. ++ This multiplication is associative and commutative. sh :(%,NNI) -> % ++ \spad{sh(x,n)} returns the shuffle power of \spad{x} to the \spad{n}. map : (R -> R, %) -> % ++ \spad{map(fn,x)} returns \spad{Sum(fn(r_i) w_i)} if \spad{x} writes \spad{Sum(r_i w_i)}. varList: % -> List vl ++ \spad{varList(x)} returns the list of variables which appear in \spad{x}. -- Attributs if R has noZeroDivisors then noZeroDivisors @ \section{category XPOLYC XPolynomialsCat} <>= import OrderedSet import XFreeAlgebra )abbrev category XPOLYC XPolynomialsCat ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ The Category of polynomial rings with non-commutative variables. ++ The coefficient ring may be non-commutative too. ++ However coefficients commute with vaiables. ++ Author: Michel Petitot (petitot@lifl.fr) XPolynomialsCat(vl:OrderedSet,R:Ring):Category == Export where WORD ==> OrderedFreeMonoid(vl) Export == XFreeAlgebra(vl,R) with maxdeg: % -> WORD ++ \spad{maxdeg(p)} returns the greatest leading word in the support of \spad{p}. degree: % -> NonNegativeInteger ++ \spad{degree(p)} returns the degree of \spad{p}. ++ Note that the degree of a word is its length. trunc : (% , NonNegativeInteger) -> % ++ \spad{trunc(p,n)} returns the polynomial \spad{p} truncated at order \spad{n}. @ \section{domain XPR XPolynomialRing} <>= import Ring import OrderedMonoid import XAlgebra import FreeMonoidCat )abbrev domain XPR XPolynomialRing ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ This domain represents generalized polynomials with coefficients ++ (from a not necessarily commutative ring), and words ++ belonging to an arbitrary \spadtype{OrderedMonoid}. ++ This type is used, for instance, by the \spadtype{XDistributedPolynomial} ++ domain constructor where the Monoid is free. ++ Author: Michel Petitot (petitot@lifl.fr) XPolynomialRing(R:Ring,E:OrderedMonoid): T == C where TERM ==> Record(k: E, c: R) EX ==> OutputForm NNI ==> NonNegativeInteger T == Join(Ring, XAlgebra(R), FreeModuleCat(R,E),CoercibleFrom E) with --operations *: (%,R) -> % ++ \spad{p*r} returns the product of \spad{p} by \spad{r}. #: % -> NonNegativeInteger ++ \spad{# p} returns the number of terms in \spad{p}. maxdeg: % -> E ++ \spad{maxdeg(p)} returns the greatest word occurring in the polynomial \spad{p} ++ with a non-zero coefficient. An error is produced if \spad{p} is zero. mindeg: % -> E ++ \spad{mindeg(p)} returns the smallest word occurring in the polynomial \spad{p} ++ with a non-zero coefficient. An error is produced if \spad{p} is zero. reductum : % -> % ++ \spad{reductum(p)} returns \spad{p} minus its leading term. ++ An error is produced if \spad{p} is zero. coef : (%,E) -> R ++ \spad{coef(p,e)} extracts the coefficient of the monomial \spad{e}. ++ Returns zero if \spad{e} is not present. constant?:% -> Boolean ++ \spad{constant?(p)} tests whether the polynomial \spad{p} belongs to the ++ coefficient ring. constant: % -> R ++ \spad{constant(p)} return the constant term of \spad{p}. quasiRegular? : % -> Boolean ++ \spad{quasiRegular?(x)} return true if \spad{constant(p)} is zero. quasiRegular : % -> % ++ \spad{quasiRegular(x)} return \spad{x} minus its constant term. map : (R -> R, %) -> % ++ \spad{map(fn,x)} returns \spad{Sum(fn(r_i) w_i)} if \spad{x} writes \spad{Sum(r_i w_i)}. if R has Field then / : (%,R) -> % ++ \spad{p/r} returns \spad{p*(1/r)}. --assertions if R has noZeroDivisors then noZeroDivisors if R has unitsKnown then unitsKnown if R has canonicalUnitNormal then canonicalUnitNormal ++ canonicalUnitNormal guarantees that the function ++ unitCanonical returns the same representative for all ++ associates of any particular element. C == FreeModule1(R,E) add --representations Rep:= List TERM --uses repeatMultExpt: (%,NonNegativeInteger) -> % --define 1 == [[1$E,1$R]] characteristic == characteristic$R #x == #$Rep x maxdeg p == if null p then error " polynome nul !!" else p.first.k mindeg p == if null p then error " polynome nul !!" else (last p).k coef(p,e) == for tm in p repeat tm.k=e => return tm.c tm.k < e => return 0$R 0$R constant? p == (p = 0) or (maxdeg(p) = 1$E) constant p == coef(p,1$E) quasiRegular? p == (p=0) or (last p).k ~= 1$E quasiRegular p == quasiRegular?(p) => p [t for t in p | not(t.k = 1$E)] recip(p) == p=0 => "failed" p.first.k > 1$E => "failed" (u:=recip(p.first.c)) case "failed" => "failed" (u::R)::% coerce(r:R) == if r=0$R then 0$% else [[1$E,r]] coerce(n:Integer) == (n::R)::% if R has noZeroDivisors then p1:% * p2:% == null p1 => 0 null p2 => 0 p1.first.k = 1$E => p1.first.c * p2 p2 = 1 => p1 -- +/[[[t1.k*t2.k,t1.c*t2.c]$TERM for t2 in p2] -- for t1 in reverse(p1)] +/[[[t1.k*t2.k,t1.c*t2.c]$TERM for t2 in p2] for t1 in p1] else p1:% * p2:% == null p1 => 0 null p2 => 0 p1.first.k = 1$E => p1.first.c * p2 p2 = 1 => p1 -- +/[[[t1.k*t2.k,r]$TERM for t2 in p2 | not (r:=t1.c*t2.c) =$R 0] -- for t1 in reverse(p1)] +/[[[t1.k*t2.k,r]$TERM for t2 in p2 | not (r:=t1.c*t2.c) =$R 0] for t1 in p1] p:% ** nn:NNI == repeatMultExpt(p,nn) repeatMultExpt(x,nn) == nn = 0 => 1 y:% := x for i in 2..nn repeat y:= x * y y outTerm(r:R, m:E):EX == r=1 => m::EX m=1 => r::EX r::EX * m::EX -- coerce(x:%) : EX == -- null x => (0$R) :: EX -- le : List EX := nil -- for rec in x repeat -- rec.c = 1$R => le := cons(rec.k :: EX, le) -- rec.k = 1$E => le := cons(rec.c :: EX, le) -- le := cons(mkBinary("*"::EX,rec.c :: EX, -- rec.k :: EX), le) -- 1 = #le => first le -- mkNary("+" :: EX,le) coerce(a:%):EX == empty? a => (0$R)::EX reduce(_+, reverse! [outTerm(t.c, t.k) for t in a])$List(EX) if R has Field then x/r == inv(r)*x @ \section{domain XDPOLY XDistributedPolynomial} Polynomial arithmetic with non-commutative variables has been improved by a contribution of Michel Petitot (University of Lille I, France). The domain constructor {\bf XDistributedPolynomial} provide a distributed representation for these polynomials. It is the non-commutative equivalent for the {\bf DistributedMultivariatePolynomial} constructor. <>= import OrderedSet import Ring import FreeModuleCat import XPolynomialRing import XPolynomialsCat )abbrev domain XDPOLY XDistributedPolynomial ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ This type supports distributed multivariate polynomials ++ whose variables do not commute. ++ The coefficient ring may be non-commutative too. ++ However, coefficients and variables commute. ++ Author: Michel Petitot (petitot@lifl.fr) XDistributedPolynomial(vl:OrderedSet,R:Ring): XDPcat == XDPdef where WORD ==> OrderedFreeMonoid(vl) I ==> Integer NNI ==> NonNegativeInteger TERM ==> Record(k:WORD, c:R) XDPcat == Join(FreeModuleCat(R, WORD), XPolynomialsCat(vl,R)) XDPdef == XPolynomialRing(R,WORD) add import( WORD, TERM) -- Representation Rep := List TERM -- local functions shw: (WORD , WORD) -> % -- shuffle de 2 mots -- definitions mindegTerm p == last(p)$Rep if R has CommutativeRing then sh(p:%, n:NNI):% == n=0 => 1 n=1 => p n1: NNI := (n-$I 1)::NNI sh(p, sh(p,n1)) sh(p1:%, p2:%) == p:% := 0 for t1 in p1 repeat for t2 in p2 repeat p := p + (t1.c * t2.c) * shw(t1.k,t2.k) p coerce(v: vl):% == coerce(v::WORD) v:vl * p:% == [[v * t.k , t.c]$TERM for t in p] mirror p == null p => p monom(mirror$WORD leadingMonomial p, leadingCoefficient p) + _ mirror reductum p degree(p) == length(maxdeg(p))$WORD trunc(p, n) == p = 0 => p degree(p) > n => trunc( reductum p , n) p varList p == constant? p => [] le : List vl := "setUnion"/[varList(t.k) for t in p] sort!(le) rquo(p:% , w: WORD) == [[r::WORD,t.c]$TERM for t in p | not (r:= rquo(t.k,w)) case "failed" ] lquo(p:% , w: WORD) == [[r::WORD,t.c]$TERM for t in p | not (r:= lquo(t.k,w)) case "failed" ] rquo(p:% , v: vl) == [[r::WORD,t.c]$TERM for t in p | not (r:= rquo(t.k,v)) case "failed" ] lquo(p:% , v: vl) == [[r::WORD,t.c]$TERM for t in p | not (r:= lquo(t.k,v)) case "failed" ] shw(w1,w2) == w1 = 1$WORD => w2::% w2 = 1$WORD => w1::% x: vl := first w1 ; y: vl := first w2 x * shw(rest w1,w2) + y * shw(w1,rest w2) lquo(p:%,q:%):% == +/ [r * t.c for t in q | (r := lquo(p,t.k)) ~= 0] rquo(p:%,q:%):% == +/ [r * t.c for t in q | (r := rquo(p,t.k)) ~= 0] coef(p:%,q:%):R == p = 0 => 0$R q = 0 => 0$R p.first.k > q.first.k => coef(p.rest,q) p.first.k < q.first.k => coef(p,q.rest) return p.first.c * q.first.c + coef(p.rest,q.rest) @ \section{domain XRPOLY XRecursivePolynomial} Polynomial arithmetic with non-commutative variables has been improved by a contribution of Michel Petitot (University of Lille I, France). The domain constructors {\bf XRecursivePolynomial} provides a recursive for these polynomials. It is the non-commutative equivalents for the {\bf SparseMultivariatePolynomial} constructor. <>= import OrderedSet import Ring import XPolynomialsCat import XDistributedPolynomial )abbrev domain XRPOLY XRecursivePolynomial ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ extend renomme en expand ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ This type supports multivariate polynomials ++ whose variables do not commute. ++ The representation is recursive. ++ The coefficient ring may be non-commutative. ++ Coefficients and variables commute. ++ Author: Michel Petitot (petitot@lifl.fr) XRecursivePolynomial(VarSet:OrderedSet,R:Ring): Xcat == Xdef where I ==> Integer NNI ==> NonNegativeInteger XDPOLY ==> XDistributedPolynomial(VarSet, R) EX ==> OutputForm WORD ==> OrderedFreeMonoid(VarSet) TERM ==> Record(k:VarSet , c:%) LTERMS ==> List(TERM) REGPOLY==> FreeModule1(%, VarSet) VPOLY ==> Record(c0:R, reg:REGPOLY) Xcat == XPolynomialsCat(VarSet,R) with expand: % -> XDPOLY ++ \spad{expand(p)} returns \spad{p} in distributed form. unexpand : XDPOLY -> % ++ \spad{unexpand(p)} returns \spad{p} in recursive form. RemainderList: % -> LTERMS ++ \spad{RemainderList(p)} returns the regular part of \spad{p} ++ as a list of terms. Xdef == add import(VPOLY) -- representation Rep := Union(R,VPOLY) -- local functions construct: LTERMS -> REGPOLY simplifie: VPOLY -> % lquo1: (LTERMS,LTERMS) -> % ++ a ajouter coef1: (LTERMS,LTERMS) -> R ++ a ajouter outForm: REGPOLY -> EX --define construct(lt) == lt pretend REGPOLY p1:% = p2:% == p1 case R => p2 case R => p1 =$R p2 false p2 case R => false p1.c0 =$R p2.c0 and p1.reg =$REGPOLY p2.reg monom(w, r) == r =0 => 0 r * w::% -- if R has Field then -- Bug non resolu !!!!!!!! -- p:% / r: R == inv(r) * p rquo(p1:%, p2:%):% == p2 case R => p1 * p2::R p1 case R => p1 * p2.c0 x:REGPOLY := construct [[t.k, a]$TERM for t in ListOfTerms(p1.reg) _ | (a:= rquo(t.c,p2)) ~= 0$% ]$LTERMS simplifie [coef(p1,p2) , x]$VPOLY trunc(p,n) == n = 0 or (p case R) => (constant p)::% n1: NNI := (n-1)::NNI lt: LTERMS := [[t.k, r]$TERM for t in ListOfTerms p.reg _ | (r := trunc(t.c, n1)) ~= 0]$LTERMS x: REGPOLY := construct lt simplifie [constant p, x]$VPOLY unexpand p == constant? p => (constant p)::% vl: List VarSet := sort(#1 > #2, varList p) x : REGPOLY := _ construct [[v, unexpand r]$TERM for v in vl| (r:=lquo(p,v)) ~= 0] [constant p, x]$VPOLY if R has CommutativeRing then sh(p:%, n:NNI):% == n = 0 => 1 p case R => (p::R)** n n1: NNI := (n-1)::NNI p1: % := n * sh(p, n1) lt: LTERMS := [[t.k, sh(t.c, p1)]$TERM for t in ListOfTerms p.reg] [p.c0 ** n, construct lt]$VPOLY sh(p1:%, p2:%) == p1 case R => p1::R * p2 p2 case R => p1 * p2::R lt1:LTERMS := ListOfTerms p1.reg ; lt2:LTERMS := ListOfTerms p2.reg x: REGPOLY := construct [[t.k,sh(t.c,p2)]$TERM for t in lt1] y: REGPOLY := construct [[t.k,sh(p1,t.c)]$TERM for t in lt2] [p1.c0*p2.c0,x + y]$VPOLY RemainderList p == p case R => [] ListOfTerms( p.reg)$REGPOLY lquo(p1:%,p2:%):% == p2 case R => p1 * p2 p1 case R => p1 *$R p2.c0 p1 * p2.c0 +$% lquo1(ListOfTerms p1.reg, ListOfTerms p2.reg) lquo1(x:LTERMS,y:LTERMS):% == null x => 0$% null y => 0$% x.first.k < y.first.k => lquo1(x,y.rest) x.first.k = y.first.k => lquo(x.first.c,y.first.c) + lquo1(x.rest,y.rest) return lquo1(x.rest,y) coef(p1:%, p2:%):R == p1 case R => p1::R * constant p2 p2 case R => p1.c0 * p2::R p1.c0 * p2.c0 +$R coef1(ListOfTerms p1.reg, ListOfTerms p2.reg) coef1(x:LTERMS,y:LTERMS):R == null x => 0$R null y => 0$R x.first.k < y.first.k => coef1(x,y.rest) x.first.k = y.first.k => coef(x.first.c,y.first.c) + coef1(x.rest,y.rest) return coef1(x.rest,y) -------------------------------------------------------------- outForm(p:REGPOLY): EX == le : List EX := [t.k::EX * t.c::EX for t in ListOfTerms p] reduce(_+, reverse! le)$List(EX) coerce(p:$): EX == p case R => (p::R)::EX p.c0 = 0 => outForm p.reg p.c0::EX + outForm p.reg 0 == 0$R::% 1 == 1$R::% constant? p == p case R constant p == p case R => p p.c0 simplifie p == p.reg = 0$REGPOLY => (p.c0)::% p coerce (v:VarSet):% == [0$R,coerce(v)$REGPOLY]$VPOLY coerce (r:R):% == r::% coerce (n:Integer) == n::R::% coerce (w:WORD) == w = 1 => 1$R (first w) * coerce(rest w) expand p == p case R => p::R::XDPOLY lt:LTERMS := ListOfTerms(p.reg) ep:XDPOLY := (p.c0)::XDPOLY for t in lt repeat ep:= ep + t.k * expand(t.c) ep - p:% == p case R => -$R p [- p.c0, - p.reg]$VPOLY p1 + p2 == p1 case R and p2 case R => p1 +$R p2 p1 case R => [p1 + p2.c0 , p2.reg]$VPOLY p2 case R => [p2 + p1.c0 , p1.reg]$VPOLY simplifie [p1.c0 + p2.c0 , p1.reg +$REGPOLY p2.reg]$VPOLY p1 - p2 == p1 case R and p2 case R => p1 -$R p2 p1 case R => [p1 - p2.c0 , -p2.reg]$VPOLY p2 case R => [p1.c0 - p2 , p1.reg]$VPOLY simplifie [p1.c0 - p2.c0 , p1.reg -$REGPOLY p2.reg]$VPOLY n:Integer * p:% == n=0 => 0$% p case R => n *$R p -- [ n*p.c0,n*p.reg]$VPOLY simplifie [ n*p.c0,n*p.reg]$VPOLY r:R * p:% == r=0 => 0$% p case R => r *$R p -- [ r*p.c0,r*p.reg]$VPOLY simplifie [ r*p.c0,r*p.reg]$VPOLY p:% * r:R == r=0 => 0$% p case R => p *$R r -- [ p.c0 * r,p.reg * r]$VPOLY simplifie [ r*p.c0,r*p.reg]$VPOLY v:VarSet * p:% == p = 0 => 0$% [0$R, v *$REGPOLY p]$VPOLY p1:% * p2:% == p1 case R => p1::R * p2 p2 case R => p1 * p2::R x:REGPOLY := p1.reg *$REGPOLY p2 y:REGPOLY := (p1.c0)::% *$REGPOLY p2.reg -- maladroit:(p1.c0)::% !! -- [ p1.c0 * p2.c0 , x+y ]$VPOLY simplifie [ p1.c0 * p2.c0 , x+y ]$VPOLY lquo(p:%, v:VarSet):% == p case R => 0 coefficient(p.reg,v)$REGPOLY lquo(p:%, w:WORD):% == w = 1$WORD => p lquo(lquo(p,first w),rest w) rquo(p:%, v:VarSet):% == p case R => 0 x:REGPOLY := construct [[t.k, a]$TERM for t in ListOfTerms(p.reg) | (a:= rquo(t.c,v)) ~= 0 ] simplifie [constant(coefficient(p.reg,v)) , x]$VPOLY rquo(p:%, w:WORD):% == w = 1$WORD => p rquo(rquo(p,rest w),first w) coef(p:%, w:WORD):R == constant lquo(p,w) quasiRegular? p == p case R => p = 0$R p.c0 = 0$R quasiRegular p == p case R => 0$% [0$R,p.reg]$VPOLY characteristic == characteristic$R recip p == p case R => recip(p::R) "failed" mindeg p == p case R => p = 0 => error "XRPOLY.mindeg: polynome nul !!" 1$WORD p.c0 ~= 0 => 1$WORD "min"/[(t.k) *$WORD mindeg(t.c) for t in ListOfTerms p.reg] maxdeg p == p case R => p = 0 => error "XRPOLY.maxdeg: polynome nul !!" 1$WORD "max"/[(t.k) *$WORD maxdeg(t.c) for t in ListOfTerms p.reg] degree p == p = 0 => error "XRPOLY.degree: polynome nul !!" length(maxdeg p) map(fn,p) == p case R => fn(p::R) x:REGPOLY := construct [[t.k,a]$TERM for t in ListOfTerms p.reg |(a := map(fn,t.c)) ~= 0$R] simplifie [fn(p.c0),x]$VPOLY varList p == p case R => [] lv: List VarSet := "setUnion"/[varList(t.c) for t in ListOfTerms p.reg] lv:= setUnion(lv,[t.k for t in ListOfTerms p.reg]) sort!(lv) @ \section{domain XPOLY XPolynomial} <>= import XRecursivePolynomial )abbrev domain XPOLY XPolynomial ++ Author: Michel Petitot petitot@lifl.fr ++ Date Created: 91 ++ Date Last Updated: 7 Juillet 92 ++ Fix History: compilation v 2.1 le 13 dec 98 ++ extend renomme en expand ++ Basic Functions: ++ Related Constructors: ++ Also See: ++ AMS Classifications: ++ Keywords: ++ References: ++ Description: ++ This type supports multivariate polynomials ++ whose set of variables is \spadtype{Symbol}. ++ The representation is recursive. ++ The coefficient ring may be non-commutative and the variables ++ do not commute. ++ However, coefficients and variables commute. ++ Author: Michel Petitot (petitot@lifl.fr) XPolynomial(R:Ring) == XRecursivePolynomial(Symbol, R) @ \section{License} <>= --Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd. --All rights reserved. -- --Redistribution and use in source and binary forms, with or without --modification, are permitted provided that the following conditions are --met: -- -- - Redistributions of source code must retain the above copyright -- notice, this list of conditions and the following disclaimer. -- -- - Redistributions in binary form must reproduce the above copyright -- notice, this list of conditions and the following disclaimer in -- the documentation and/or other materials provided with the -- distribution. -- -- - Neither the name of The Numerical ALgorithms Group Ltd. nor the -- names of its contributors may be used to endorse or promote products -- derived from this software without specific prior written permission. -- --THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS --IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED --TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A --PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER --OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, --EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, --PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR --PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF --LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING --NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS --SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. @ <<*>>= <> <> <> <> <> <> <> <> <> <> <> @ \eject \begin{thebibliography}{99} \bibitem{1} nothing \end{thebibliography} \end{document}