Keisuke Kodaira

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By a complex 4-manifold we shall mean a complex manifold of topological dimension 4. For any complex 4-manifold M we let cv(M) denote the v th Chern class of M. By the Hirzebruch index theorem, the index of M is equal to 9 = 31-(m)-2c2(m)]. A. Van de Ven has pointed out in connection with his recent results(1) that there are not many known examples of(More)
Entanglement-assisted quantum error-correcting (EAQEC) codes, a wider class of stabilizer codes, allow us to construct quantum error-correcting codes from arbitrary classical codes with the help of ebits, i.e. maximally entangled quantum states. However, in the construction of EAQEC codes, it is desirable to use as small number of ebits as possible because(More)
Let (W, ω) be a smooth projective algebraic variety of dimension 2n over C together with a holomorphic (2, 0)-form of maximal rank 2n. A subvariety X ⊂ W is called weakly lagrangian if dim X ≤ n and if the restriction of ω to X is trivial (notice that X can be singular). An n-dimensional subvariety X ⊂ W with this property is called lagrangian. For example,(More)