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jakobkroeker / test_singular

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preimage bug; overflow? #155

Closed jakobkroeker closed 9 years ago

jakobkroeker commented 9 years ago 
LIB("primdec.lib");
ring R = 0,(x,y),dp;
short = 0;
ring G = 0,(a,b),dp;
short = 0;
ideal phi = a^3,b;
map m = R,phi;
ideal I = a^131070;
setring R;
ideal pI = preimage(G,m,I);
pI;
ideal pIexpected =  x^43690;
setring G;
ideal mpIexpected = m(pIexpected);
mpIexpected;
ASSUME(0, idealsEqual(mpIexpected , I) );

ideal mpI = m(pI);
mpI;
ASSUME(0, idealsEqual(mpI , I) );

upstream report: http://www.singular.uni-kl.de:8002/trac/ticket/698 (Hans argues that exponent limit is documented) update: the overflow is now detected TODO: look for new examples

jakobkroeker commented 9 years ago

test : https://github.com/Singular/Sources/commit/0b9aa7febb094f9895da3d802b389bd9560e3c48

fixes: https://github.com/Singular/Sources/commit/fc77091687ca4452f82b084b30f8522dec3b357d https://github.com/Singular/Sources/commit/971ba398c4e59220edcf880bdcc5a0948ba9d17c

see also #83