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Normalized Volume


The normalized volume of a Kawamata log terminal pair at a point is the infimum of discrepancy-weighted volumes of valuations centered at that point. For an n-dimensional normal complex algebraic germ (X,x) with rational Cartier canonical divisor and zero boundary, assume (X,0) is Kawamata log terminal. A real-valued additive valuation v centered at x has ideals a_t(v)={f in O_(X,x):v(f)>=t} and volume

 vol(v)=lim_(t->infty)(n!l(O_(X,x)/a_t(v)))/(t^n),

where l denotes module length. The normalized volume of the germ is

 vol^^(x,X)=inf_(v)A_X(v)^nvol(v).

Here A_X is log discrepancy and valuations of infinite discrepancy contribute +infty. The expression is invariant under positive rescaling of v.

The smooth-point value is n^n.


See also

Additive Valuation, Kawamata Log Terminal Pair, Local Ring, Module Length, Ordinary Double Point

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References

Li, C. "Minimizing Normalized Volumes of Valuations." Math. Z. 289, 491-513, 2018. https://doi.org/10.1007/s00209-017-1963-3.Li, C.; Liu, Y.; and Xu, C. "A Guided Tour to Normalized Volume." In Geometric Analysis: In Honor of Gang Tian's 60th Birthday (Ed. J. Chen, P. Lu, Z. Lu, and Z. Zhang). Cham, Switzerland: Birkhäuser, pp. 167-219, 2020. https://doi.org/10.1007/978-3-030-34953-0_10.

Cite this as:

Weisstein, Eric W. "Normalized Volume." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/NormalizedVolume.html

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