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    "可微分的凸函数 $f: \\mathbb{R}^d \\to \\mathbb{R}$ 和 $g: \\mathbb{R}^d \\to \\mathbb{R}^p$ 的约束条件的最小化问题：\n",
    "\n",
    "$$\n",
    "\\mathop{\\min}_{t} f(t), g(t) \\leqslant 0\n",
    "$$\n",
    "\n",
    "可以转换为拉格朗日对偶问题重新定义：\n",
    "\n",
    "$$\n",
    "\\mathop{\\max}_{\\lambda} \\mathop{\\inf}_{t} L(t, \\lambda), \\lambda \\geqslant 0\n",
    "$$\n",
    "\n",
    "其中，$\\lambda$ 称为拉格朗日乘子：\n",
    "\n",
    "$$\n",
    "\\lambda = (\\lambda_1, \\dots, \\lambda_p)^T\n",
    "$$\n",
    "\n",
    "$L(t, \\lambda)$ 称为拉格朗日函数：\n",
    "\n",
    "$$\n",
    "L(t, \\lambda) = f(t) + \\lambda^Tg(t)\n",
    "$$\n",
    "\n",
    "拉格朗日对偶问题的 t 的解，与原来的问题的解是一致的。"
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