Existence prolem的用法和樣例：
例句
- Thus educational problems consist of the problem of human being and existence.
人的存有與存在問題恰恰構成教育的問題核心。 - The problem of the blending of the quadratic and thrice algebraic surfaces is transformed into the existence of the nonzero solution of some homogeneous linear equations.
摘要將一個二次曲面和一個三次曲面沿平面介面的拼接曲面的存在性轉化為求三個多項式理想交的成員問題，進而化為一組齊次線性方程組的非零解的存在問題。
