PolynomialIdeals
Intersect
intersect two or more ideals
Calling Sequence
Parameters
Description
Examples
References
Intersect(J, K, ...)
J, K
-
polynomial ideals
The Intersect command computes the intersection of two or more polynomial ideals. The set of variables is extended to include the variables of each ideal. If the ideals cannot be put into a common polynomial ring, then an error is produced.
The Intersect command makes extensive use of generators that are common to one or more of the ideals. Thus for certain applications, such as intersecting prime components, avoid using the Simplify command prior to using Intersect.
with⁡PolynomialIdeals:
J≔x⁢x−1,y2⁢y−2
K≔x−12⁢y3
L≔Intersect⁡J,K
L≔x3⁢y3−2⁢x2⁢y3+x⁢y3,x2⁢y4−2⁢x2⁢y3−2⁢x⁢y4+4⁢x⁢y3+y4−2⁢y3
map⁡factor,Generators⁡L
x⁢y3⁢x−12,y3⁢x−12⁢y−2
Trinks≔45⁢p+35⁢s−165⁢b−36,35⁢p+40⁢z+25⁢t−27⁢s,15⁢w+25⁢p⁢s+30⁢z−18⁢t−165⁢b2,−9⁢w+15⁢p⁢t+20⁢z⁢s,w⁢p+2⁢z⁢t−11⁢b3,99⁢w−11⁢s⁢b+3⁢b2:
P≔PrimeDecomposition⁡Trinks
P≔35⁢p+40⁢z+25⁢t−27⁢s,45⁢p+35⁢s−165⁢b−36,10000⁢b2+6600⁢b+2673,3⁢b2−11⁢s⁢b+99⁢w,−11⁢b3+w⁢p+2⁢z⁢t,15⁢p⁢t+20⁢z⁢s−9⁢w,−165⁢b2+25⁢p⁢s−18⁢t+15⁢w+30⁢z,35⁢p+40⁢z+25⁢t−27⁢s,45⁢p+35⁢s−165⁢b−36,3⁢b2−11⁢s⁢b+99⁢w,−11⁢b3+w⁢p+2⁢z⁢t,15⁢p⁢t+20⁢z⁢s−9⁢w,−165⁢b2+25⁢p⁢s−18⁢t+15⁢w+30⁢z,4380800000000000⁢b8+16108202000000000⁢b7+22514571860000000⁢b6+18624678595600000⁢b5+9432310305572000⁢b4+2959977269862580⁢b3+617295990812985⁢b2+80609374775160⁢b+3361317558192
Intersect⁡P
45⁢p+35⁢s−165⁢b−36,360⁢z+225⁢t−488⁢s+1155⁢b+252,−3⁢b2+11⁢s⁢b−99⁢w,720⁢b2+100⁢s2+495⁢b−312⁢s+189⁢t−4320⁢w+108,9780⁢b3+5511⁢b2+2541⁢b⁢t−54780⁢b⁢w+12100⁢s⁢w+1452⁢b−37752⁢w,31905⁢b2−8250⁢b⁢t+3625⁢s⁢t+20130⁢b−10588⁢s+5886⁢t−87705⁢w+4392,−3517910176905⁢b2−1957980036375⁢b⁢t−41699992620000⁢b⁢w+2053884110000⁢s⁢w+6296364000000⁢t⁢w−4270660634130⁢b+3051085536688⁢s−2793459284586⁢t+9307987795080⁢w−1203227496792,1878597945⁢b2−277744500⁢b⁢t+6163080000⁢b⁢w−1364740000⁢s⁢w+132946875⁢t2+1427525220⁢b−842211872⁢s+617096484⁢t−2545409520⁢w+349357248,217116000000⁢b2⁢t−523021633605⁢b2−231486118875⁢b⁢t−9181541820000⁢b⁢w+1498470710000⁢s⁢w−651341592330⁢b+472703393008⁢s−432789466626⁢t+608907986280⁢w−186415527672,31183768112939065344000000000000⁢w3−4383898761959271072221964848415⁢b2−7903710355804657299210818786625⁢b⁢t−117103813087016017731632275860000⁢b⁢w+12316920319203058988534335330000⁢s⁢w−137137883064576891898454400000000⁢w2−8702178744906158552643521345790⁢b+7447021570649738370655533213584⁢s−7784271516314849432429864858598⁢t+21118050431651645563189897792440⁢w−2801807632629602942921244631656,338965791342080000000000⁢s⁢w2+221155529291376910543935⁢b2+375421939762061941934625⁢b⁢t+5590055517660268491540000⁢b⁢w−584789005513826862370000⁢s⁢w+6837072534440841600000000⁢w2+422013879012204865685310⁢b−356171590884671762712976⁢s+370234284729884595453222⁢t−1039943191683735694847160⁢w+134345134485535123713384,156602195600040960000000000⁢b⁢w2+67616116062115359652310385⁢b2+114854703032577754306083375⁢b⁢t+1739802332651675509271340000⁢b⁢w−187872451101953392294270000⁢s⁢w+2062650565630151337600000000⁢w2+130204742924375556672575010⁢b−110656861555918546136790896⁢s+115092438872369240664523962⁢t−304732879233181539528924360⁢w+41720006256591398587472664,649952667840000000⁢b2⁢w−160178876945916915⁢b2−405324636049414125⁢b⁢t−5542640048550660000⁢b⁢w+467514361356730000⁢s⁢w−9508517058240000000⁢w2−412686923010127590⁢b+377102729779293584⁢s−403888404899889198⁢t+892474508950948440⁢w−140557774363306056
Cox, D.; Little, J.; and O'Shea, D. Ideals, Varieties, and Algorithms. 2nd ed. New York: Springer-Verlag, 1997.
See Also
PolynomialIdeals[EliminationIdeal]
PolynomialIdeals[Generators]
PolynomialIdeals[PrimeDecomposition]
PolynomialIdeals[Simplify]
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