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D.5.5.11 intersection
Procedure from library hnoether.lib (see hnoether_lib).
- Usage:
- intersection(hne1,hne2); hne1, hne2 lists
- Assume:
- hne1, hne2 represent a HNE (i.e., are the output of
develop(f) , or of extdevelop(develop(f),n) , or
one entry of the output of reddevelop(f) ).
- Return:
- int, the intersection multiplicity of the branches corresponding to
hne1 and hne2.
Example:
| LIB "hnoether.lib";
// -------- prepare for example ---------
if (nameof(basering)=="HNEring") {
def rettering=HNEring;
kill HNEring;
}
// ------ the example starts here -------
int plevel=printlevel; printlevel=-1;
ring r=0,(x,y),dp;
list hne=reddevelop((x2-y3)*(x2+y3));
intersection(hne[1],hne[2]);
==> 6
kill HNEring,r;
printlevel=plevel;
// --- restore HNEring if previously defined ---
if (defined(rettering)) {
setring rettering;
def HNEring=rettering;
export HNEring;
}
| See also:
displayInvariants;
reddevelop.
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