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{\bf Nagi H. Nahas}
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{\bf On the Crossing Number of $K_{m,n}$}
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The  best lower bound known on the crossing number
of the complete bipartite graph is :
$$cr(K_{m,n}) \geq (1/5)(m)(m-1)\lfloor n/2 \rfloor \lfloor(n-1)/2\rfloor$$
In this paper we prove that:
$$cr(K_{m,n}) \geq (1/5)m(m-1)\lfloor n/2 \rfloor \lfloor (n-1)/2
\rfloor + 9.9 \times 10^{-6} m^2n^2$$
for sufficiently large $m$ and $n$.

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