I guess this is correct.

来源: 乱弹 于 2009-03-04 17:50:00 [] [博客] [旧帖] [给我悄悄话] 阅读数 : (200 bytes)
本帖于 2009-03-18 18:55:04 时间, 由普通用户 康MM 编辑
回答: 2005全国高中数学联赛 -- 正方形剖分 由 于德利 于 2009-03-01 05:07:09

Basically using Euler's formula, V-E+F=1, where F=2005.
Besides the four corners, every vertex is of degree at least 3, so we have 8+3(V-4) ≤ 2E. Combine these two, we get the answer.

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