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{
"source_file": "./raw_volume-zh/volume1/exercise1.tex",
"problem_type": "calculation",
"problem": "问题9: 已知 $M=\\left\\{x \\mid x=a^2+1, a \\in \\mathbf{N}^*\\right\\}, N=\\left\\{x \\mid x=b^2-4 b+5, b \\in \\mathbf{N}^*\\right\\}$, 则 $M$ 与 $N$ 的关系是",
"solution": "解: $M \\varsubsetneqq N$. 由 $a^2+1=(a+2)^2-4 a+5$ 知 $M \\subseteq N$. 但 $1 \\in N, 1 \\notin M$.",
"remark": "",
"figures": []
} |