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D.15.1.17 determineExceptionalHypersurface

Procedure from library arnold.lib (see arnold_lib).

Usage:
determineExceptionalHypersurface(N); N a NormalForm as given by @ref(determineNormalForm)

Return:
a polynomial defining the exceptional hypersurface for the normal form stored in N.normalForm, i.e. the parameter values that are not allowed for N.normalForm, stored in N.exceptionalHypersurface

Example:
 
LIB "arnold.lib";
ring R = 0,(x,y,z),ds;
poly g = x^2*y^4+y^2*x^4+5*x^(10)+y^(11)+z^2;
poly phix = x+y^2+x^2+x*y+x^2*y+x*y^3;
poly phiy = y+y^2+2*x^2+x*y+y*x^2+y^2*x+x*y^4;
poly phiz = z+2*x+x^2+y^4*x;
map phi = R,phix,phiy,phiz;
g = phi(g);
Poly F = makePoly(g);
NormalForm N= determineNormalForm(F);
determineExceptionalHypersurface(N);
==> Embedding dimension = 3
==> Corank of singularity = 2
==> Normal form of type = (0,11),(2,4),(4,2),(7,1),(35,0)
==> Normal form = (a(4))*x^4*y^2+(a(5))*x^3*y^3+(a(6))*x^2*y^4+(a(2))*x^4*y^3\
   +(a(3))*x^3*y^4+x^7*y+(a(1))*x^4*y^4+y^11+x^35
==> Exceptional Hypersurface = a(4)*a(5)^2*a(6)-4*a(4)^2*a(6)^2
==> Normal form equation is not determined.
==> Milnor number = 34
==> Modality = 6
==> Monomials corresponding to moduli terms = x^4*y^4, x^4*y^3, x^3*y^4, x^4*\
   y^2, x^3*y^3, x^2*y^4
==> Delta invariant = 19
==> Number of branches = 5
==> Determinacy <= 13
==> Non-degenerate part = z^2
==> Chain of transformations before Morse split of length 5
==> Chain of transformations after Morse split of length 4
==> 
==> The chain of transformations is only containing transformations up to tra\
   nsforming the input polynomial to a germ with a nondegenerate Newton boun\
   dary. The final transformations to normalize the germ are not yet determi\
   ned.
==> 


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