Seshadri constant
In algebraic geometry, a Seshadri constant is an invariant of an ample line bundle L at a point P on an algebraic variety. It was introduced by Demailly to measure a certain rate of growth, of the tensor powers of L, in terms of the jets of the sections of the Lk. The object was the study of the Fujita conjecture. The name is in honour of the Indian mathematician C. S. Seshadri. It is known that Nagata's conjecture on algebraic curves is equivalent to the assertion that for more than nine general points, the Seshadri constants of the projective plane are maximal. There is a general conjecture for algebraic surfaces, the Nagata–Biran conjecture. Definition
Let  be a smooth projective variety,  an ample line bundle on it,  a point of ,  = { all irreducible curves passing through  }. . Here,  denotes the intersection number of  and ,  measures how many times  passing through . Definition: One says that  is the Seshadri constant of  at the point , a real number. When  is an abelian variety, it can be shown that  is independent of the point chosen, and it is written simply . References

Algebraic varieties
Vector bundles
Mathematical constants