# OpenMath Content Dictionary: polynomial4

Canonical URL:
http://www.win.tue.nl/SCIEnce/cds/polynomial4.ocd
CD File:
polynomial4.ocd
CD as XML Encoded OpenMath:
polynomial4.omcd
Defines:
definitely_irreducible, divide, factor, factorisations, factorisations_complete, factorisations_incomplete, factorise, factors, ground_ring_injected, multiplicity, possibly_reducible, quotient, quotient_remainder, remainder
Date:
2009-06-22
Version:
0 (Revision 4)
Review Date:
Status:
experimental
Uses CD:
alg1, polyd1

This CD holds a collection of for some operations of polynomials over rings. The data structures for polynomials can be arithmetic expressions, for instance using the ring1.expression symbol, or DMP as in the CD polyd1.

## factorise

Description:
This symbol is a unary function, whose argument should be a polynomial f. When applied to f, it represents a list of factors of f. Cf. polynomial4.factorisations for a description of the expected reply.
Example:

$\mathrm{factorise}\left(\mathrm{DMP}\left(\mathrm{poly_ring_d_named}\left(\mathbb{Z},X\right),\mathrm{SDMP}\left(\mathrm{term}\left(1,2\right),\mathrm{term}\left(-1,0\right)\right)\right)\right)$
Signatures:
sts

 [Next: factorisations] [Last: remainder] [Top]

## factorisations

Description:
This symbol may be used in the reply of polynomial4.factorise and takes at least 1 argument. The first argument is one of polynomial4.factorisations_complete to indicate that the following list of polynomial4.factors cells covers all possible factorisations. The counterpart would be polynomial4.factorisations_possibly_incomplete to indicate that the following list of factorisations are some of possibly many more factorisations. Note: If the polynomial algebra is a UFD (unique factorisation domain) the uniqueness can be underpinned by giving exactly one polynomial4.factors cell and using the symbol polynomial4.factorisations_complete here. The rest of the arguments are polynomial4.factors cells, each of which being a possible factorisation. Using the call of polynomial4.factorise above we might obtain:
Example:

$\mathrm{factorisations}\left(\mathrm{factorisations_complete},\mathrm{factors}\left(\mathrm{definitely_irreducible},\mathrm{poly_ring_d_named}\left(Z,X\right),1,\mathrm{factor}\left(\mathrm{DMP}\left(\mathrm{poly_ring_d_named}\left(Z,X\right),\mathrm{SDMP}\left(\mathrm{term}\left(1,1\right),\mathrm{term}\left(-1,0\right)\right)\right),\mathrm{multiplicity}\left(1\right)\right),\mathrm{factor}\left(\mathrm{DMP}\left(\mathrm{poly_ring_d_named}\left(Z,X\right),\mathrm{SDMP}\left(\mathrm{term}\left(1,1\right),\mathrm{term}\left(1,0\right)\right)\right),\mathrm{multiplicity}\left(1\right)\right)\right)\right)$
Signatures:
sts

 [Next: factors] [Previous: factorise] [Top]

## factors

Description:
This symbol is used in the reply of polynomial4.factorise and takes at least 2 arguments. Note this symbol may also be used in a polynomial4.factorisations cell. The first argument is one of polynomial4.definitely_irreducible or polynomial4.possibly_reducible and specifies whether the computed factorisation is known to be irreducible or if the irreducibility of some of the factors is not guaranteed. Note: This symbol is mandatory even if the factors themselves (see polynomial4.factor) can carry that information, this is simply to connive at computer algebra systems that cannot figure out which of the factors is the possibly reducible one. Generally this slot must be polynomial4.possibly_reducible if at least one of the factors is possibly reducible. The second argument contains a polyd1.poly_ring_d or polyd1.poly_ring_d_named cell, as specified in e.g. polyd or polyd1 to indicate the underlying polynomial algebra. The third argument is a symbol polynomial4.common_coefficient and denotes the common coefficient of the factorisation. Note: In case the ground ring itself is regarded as being injected into the polynomial algebra, or the factorisation is normalised, this field may be used to specify the unit giving the normalisation. Furthermore, the cell comprises polynomial4.factor cells which in turn represent the factors of the polynomial in a factorisation along with their multiplicities. Using the call of polynomial4.factorise above we might obtain:
Example:

$\mathrm{factors}\left(\mathrm{definitely_irreducible},\mathrm{poly_ring_d_named}\left(Z,X\right),1,\mathrm{factor}\left(\mathrm{DMP}\left(\mathrm{poly_ring_d_named}\left(Z,X\right),\mathrm{SDMP}\left(\mathrm{term}\left(1,1\right),\mathrm{term}\left(-1,0\right)\right)\right),\mathrm{multiplicity}\left(1\right)\right),\mathrm{factor}\left(\mathrm{DMP}\left(\mathrm{poly_ring_d_named}\left(Z,X\right),\mathrm{SDMP}\left(\mathrm{term}\left(1,1\right),\mathrm{term}\left(1,0\right)\right)\right),\mathrm{multiplicity}\left(1\right)\right)\right)$
Signatures:
sts

 [Next: factor] [Previous: factorisations] [Top]

## factor

Description:
A symbol which represents one factor of a factorisation, it takes at least 2 arguments, the first of which being the factor polynomial, e.g. a polyd1.DMP, and the second being its multiplicity specified as an integer >= 1. Optionally, the third argument is one of polynomial4.definitely_irreducible, polynomial4.possibly_reducible to indicate whether or not the given factor is guaranteed to be irreducible. Furthermore, this symbol may contain polynomial4.ground_ring_injected to indicate that the ground ring is considered to be embedded in the polynomial algebra and hence the factor is actually the factorisation of a polynomial coefficient.
Signatures:
sts

 [Next: multiplicity] [Previous: factors] [Top]

## multiplicity

Description:
A symbol which represents the multiplicity of a factor in a factorisation and takes exactly one argument which must be a positive integer.
Signatures:
sts

 [Next: factorisations_complete] [Previous: factor] [Top]

## factorisations_complete

Description:
A symbol to indicate that a given list of factorisations of a polynomial covers in fact all possible factorisations.
Signatures:
sts

 [Next: factorisations_incomplete] [Previous: multiplicity] [Top]

## factorisations_incomplete

Description:
A symbol to indicate that a given list of factorisations is an assortment of all possible factorisations.
Signatures:
sts

 [Next: definitely_irreducible] [Previous: factorisations_complete] [Top]

## definitely_irreducible

Description:
A symbol which denotes that a factor of the factorisation is definitely irreducible.
Signatures:
sts

 [Next: possibly_reducible] [Previous: factorisations_incomplete] [Top]

## possibly_reducible

Description:
A symbol which denotes that the irreducibility of a factor of the factorisation is not guaranteed.
Signatures:
sts

 [Next: ground_ring_injected] [Previous: definitely_irreducible] [Top]

## ground_ring_injected

Description:
A symbol which denotes that the ground ring of a polynomial algebra is considered to be part of the latter. This is used in the polynomial4.factor symbol to indicate that the factor is part of the factorisation of the common coefficient.
Signatures:
sts

 [Next: divide] [Previous: possibly_reducible] [Top]

## divide

Description:
This symbol is a binary function whose arguments are polynomials f and g which must be defined over the same ground domain. When applied to f and g, it represents the quotient arising from dividing f by g and the remainder h such that h is congruent f modulo g. The result is gathered in a polynomial4.quotient_remainder cell. Hint: We consider named polynomial rings, i.e. the indeterminate is explicitly specified by a named variable, different once the variable names differ. That is, a polynomial in Z[X] cannot be divided by a polynomial in Z[Y] a priori. However, we leave it up to the implementor to handle this differently, though we strongly encourage implementors to return a polynomial in an anonymous indeterminate (using e.g. polyd1.poly_ring_d rather than polyd1.poly_ring_d_named).
Example:

$\mathrm{divide}\left(\mathrm{DMP}\left(\mathrm{poly_ring_d}\left(Z,1\right),\mathrm{SDMP}\left(\mathrm{term}\left(1,5\right),\mathrm{term}\left(2,3\right),\mathrm{term}\left(1,0\right)\right)\right),\mathrm{DMP}\left(\mathrm{poly_ring_d}\left(Z,1\right),\mathrm{SDMP}\left(\mathrm{term}\left(1,2\right),\mathrm{term}\left(1,0\right)\right)\right)\right)$
Signatures:
sts

 [Next: quotient_remainder] [Previous: ground_ring_injected] [Top]

## quotient_remainder

Description:
This symbol is a container for the result of polynomial4.divide. It takes 2 arguments in unspecified order, polynomial4.quotient and polynomial4.remainder. Using the above polynomial4.divide call we may obtain:
Example:

$\mathrm{quotient_remainder}\left(\mathrm{quotient}\left(\mathrm{DMP}\left(\mathrm{poly_ring_d}\left(Z,1\right),\mathrm{SDMP}\left(\mathrm{term}\left(1,3\right),\mathrm{term}\left(1,1\right)\right)\right)\right),\mathrm{remainder}\left(\mathrm{DMP}\left(\mathrm{poly_ring_d}\left(Z,1\right),\mathrm{SDMP}\left(\mathrm{term}\left(-1,1\right),\mathrm{term}\left(1,0\right)\right)\right)\right)\right)$
Signatures:
sts

 [Next: quotient] [Previous: divide] [Top]

## quotient

Description:
This symbol contains the quotient of polynomial4.divide. Cf. polynomial4.quotient_remainder for an example.
Signatures:
sts

 [Next: remainder] [Previous: quotient_remainder] [Top]

## remainder

Description:
This symbol contains the remainder of polynomial4.divide. Cf. polynomial4.quotient_remainder for an example.
Signatures:
sts

 [First: factorise] [Previous: quotient] [Top]