Singular Manual: constructblwup

| #### D.5.5.22 constructblwup Procedure from library `resbinomial.lib` (see resbinomial_lib). Usage: constructblwup(blwhist,n,chy,flag); blwhist, flag lists, n integer, chy ideal Return: the ideal defining the map K[W] --> K[Wi], which gives the composition map of all the blowing up leading to this chart Note: NECESSARY START WITH COLUMNS Example:
    LIB "resbinomial.lib";
    ring r = 0,(x(1..3)),dp;
    list flag=identifyvar();
    ideal chy=maxideal(1);
    ideal J=x(1)^4*x(2)^2, x(1)^2+x(3)^3;
    list L=Eresol(J);   // 7 charts
    // history of the blow ups at the 7-th chart, center {x(1)=x(3)=0} every time
    L[1][7][8]; // blow ups at x(3)-th, x(1)-th and x(1)-th charts
    ==> [1]:
    ==>    0,3,0,0
    ==> [2]:
    ==>    0,0,0,0
    ==> [3]:
    ==>    0,0,1,1
    constructblwup(L[1][7][8],3,chy,flag);
    ==> _[1]=x(1)^3*x(3)
    ==> _[2]=x(2)
    ==> _[3]=x(1)^2*x(3)

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