The OrePoly Structure
An Ore polynomial is represented by an OrePoly structure. It consists of the constructor OrePoly with a sequence of coefficients starting with the one of degree zero. For example, in the differential case with the differential operator D, OrePoly(2/x, x, x+1, 1) represents the operator 2/x+xD+(x+1)D^2+D^3.
For a brief review of pseudo-linear algebra (also known as Ore algebra), see OreAlgebra.
Examples
with⁡OreTools:
Define the differential algebra.
A≔SetOreRing⁡x,differential
A≔UnivariateOreRing⁡x,differential
Poly≔OrePoly⁡2⁢3⁢x+1x2⁢4+27⁢x,−2x⁢4+27⁢x,1
Apply⁡Poly,f⁡x,A
2⁢3⁢x+1⁢f⁡xx2⁢4+27⁢x−2⁢ⅆⅆxf⁡xx⁢4+27⁢x+ⅆ2ⅆx2f⁡x
Define the shift algebra.
A≔SetOreRing⁡n,shift
A≔UnivariateOreRing⁡n,shift
Poly≔OrePoly⁡1,−2,−2,1
Apply⁡Poly,s⁡n,A
s⁡n−2⁢s⁡n+1−2⁢s⁡n+2+s⁡n+3
Define the q-shift algebra.
A≔SetOreRing⁡x,q,qshift
A≔UnivariateOreRing⁡x,qshift
Poly≔OrePoly⁡−q⁢1−q⁢x,1
Poly≔OrePoly⁡−q⁢−q⁢x+1,1
Apply⁡Poly,s⁡x,A
−q⁢−q⁢x+1⁢s⁡x+s⁡q⁢x
See Also
OreTools
OreTools/Apply
OreTools/OreAlgebra
OreTools/SetOreRing
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