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Tight Stochastic Sequential Covers for General VC Classes with Unknown i.i.d. Features

arXiv机器学习 2026-10-31 18:00 5 阅读 查看原文
1. 分析请求: * 角色:专业的新闻排版工程师。 * 任务:将纯文本新闻正文排版成语义化的HTML片段。 * 规则: 1. 只输出HTML片段,无Markdown围栏,无解释。 2. 每个自然段落用 `

` 包裹,长文用 `

`/`

` 划分小节。 3. 列表用 `
  • `,引用用 `
    `,代码用 `
    `,重要句子可用 ``。
            4. 保留原文所有信息,不得增删改内容。
            5. 不要输出 ``/``/`` 等文档级标签。
        *   正文内容:
            "We study hybrid online learning with stochastic features and adversarial labels when the feature distribution is unknown. Prior work gave stochastic sequential covers of log-size $O(d\log^2 T)$ for a general VC class and logarithmic bounds only under stronger star-type structure. We show that finite VC dimension alone is enough: every binary class of VC dimension $d$ admits a distribution-blind exact cover with log-size $O(d\log T+\log(1/δ))$, matching the worst-case $Ω(d\log(T/d))$ dependence on the horizon. The key ingredient is a new local cube weight that counts Boolean subcubes incident to each realizable trace. Unlike the equal splits used in earlier constructions, we split mass unevenly according to these cube weights; a coordinate-deletion inequality shows that VC dimension controls the total cost of these splits. This yields, to our knowledge, the first tight $O((d+1)\log T)$ expected worst-case log-loss regret for general VC partitions with unknown i.i.d. features, and an exact polynomial-time implementation for planar affine halfspaces. We also show that the binary phenomenon does not extend from VC dimension to pseudo-dimension: a fixed pseudo-dimension-one sigmoid class requires $Ω(\log^2 T)$ bits for uniform sequential approximation at accuracy $1/T$."
    
    2.  解构正文内容:
        *   这是一段学术摘要,没有显式的“列表”或“引用”,但包含多个逻辑层次和关键结论。
        *   主题:混合在线学习,随机特征,对抗标签,未知特征分布。
        *   段落1:介绍研究背景和先前工作。
            "We study hybrid online learning with stochastic features and adversarial labels when the feature distribution is unknown. Prior work gave stochastic sequential covers of log-size $O(d\log^2 T)$ for a general VC class and logarithmic bounds only under stronger star-type structure."
        *   段落2:本文的核心贡献(主要结果)。
            "We show that finite VC dimension alone is enough: every binary class of VC dimension $d$ admits a distribution-blind exact cover with log-size $O(d\log T+\log(1/δ))$, matching the worst-case $Ω(d\log(T/d))$ dependence on the horizon." -> 这句话很重要,可以用 `` 包裹,或者将 "We show that finite VC dimension alone is enough" 部分加粗。
        *   段落3:关键方法/技术。
            "The key ingredient is a new local cube weight that counts Boolean subcubes incident to each realizable trace. Unlike the equal splits used in earlier constructions, we split mass unevenly according to these cube weights; a coordinate-deletion inequality shows that VC dimension controls the total cost of these splits."
        *   段落4:具体应用/推论。
            "This yields, to our knowledge, the first tight $O((d+1)\log T)$ expected worst-case log-loss regret for general VC partitions with unknown i.i.d. features, and an exact polynomial-time implementation for planar affine halfspaces."
        *   段落5:负结果/进一步讨论。
            "We also show that the binary phenomenon does not extend from VC dimension to pseudo-dimension: a fixed pseudo-dimension-one sigmoid class requires $Ω(\log^2 T)$ bits for uniform sequential approximation at accuracy $1/T$."
    
    3.  设计HTML结构:
        *   由于是单段摘要,可以加一个 `

    ` 作为标题,比如 `

    研究背景与核心贡献

    `,但规则说“不得增删改内容”,所以不能随便加标题,除非为了划分小节。 * 规则2:“每个自然段落用

    包裹,长文用

    /

    划分小节”。 * 既然原文没有明确的小节标题,我可以将原文的自然段落用 `

    ` 包裹。 * 如果要把长文划分小节,我可以提取第一句作为小节标题吗?不行,规则4“不得增删改内容”。 * 那就直接用 `

    ` 包裹每个自然段。原文看起来是一整段,但我可以按照语义将其拆分成几个 `

    ` 标签,只要不改变字词。 * 或者,既然它是一整段,我就用一个 `

    ` 包裹整段?不,通常摘要会分段。为了排版美观,按句群或逻辑块拆分成多个 `

    ` 是合理的,只要文字完全一致。 * 让我们把原文拆成5个逻辑段落(对应上面的5个句子群)。 * 加粗关键结论: * We show that finite VC dimension alone is enough: every binary class... * The key ingredient is a new local cube weight... * This yields, to our knowledge, the first tight $O((d+1)\log T)$ expected worst-case log-loss regret... * 数学公式:规则提到“代码用

    ”,这里公式是用 `$...$` 包裹的 LaTeX 格式,不是代码块。规则3说“代码用
    ”,但通常数学公式不需要变成代码块,除非特别要求。规则3“代码用
    ”,这里没有代码,只有数学公式。为了安全起见,保持公式原样,或者把公式当作行内代码?不,原文是 `$O(d\log^2 T)$`,直接保留文本即可,不需要转义。如果严格说“代码”,这里并没有编程语言代码。所以直接输出文本。
        *   等等,规则说“重要句子可用”。
        *   让我们仔细拆分段落:
    
        原文:
        We study hybrid online learning with stochastic features and adversarial labels when the feature distribution is unknown. Prior work gave stochastic sequential covers of log-size $O(d\log^2 T)$ for a general VC class and logarithmic bounds only under stronger star-type structure.
    
        We show that finite VC dimension alone is enough: every binary class of VC dimension $d$ admits a distribution-blind exact cover with log-size $O(d\log T+\log(1/δ))$, matching the worst-case $Ω(d\log(T/d))$ dependence on the horizon.
    
        The key ingredient is a new local cube weight that counts Boolean subcubes incident to each realizable trace. Unlike the equal splits used in earlier constructions, we split mass unevenly according to these cube weights; a coordinate-deletion inequality shows that VC dimension controls the total cost of these splits.
    
        This yields, to our knowledge, the first tight $O((d+1)\log T)$ expected worst-case log-loss regret for general VC partitions with unknown i.i.d. features, and an exact polynomial-time implementation for planar affine halfspaces.
    
        We also show that the binary phenomenon does not extend from VC dimension to pseudo-dimension: a fixed pseudo-dimension-one sigmoid class requires $Ω(\log^2 T)$ bits for uniform sequential approximation at accuracy $1/T$.
    
        4.  应用规则检查:
            - 只输出HTML片段本身?是。
            - 不要Markdown围栏、不要解释?是。
            - 每个自然段落用

    包裹?是,按逻辑拆分成5个

    。 - 长文用

    /

    划分小节?由于原文没有小标题,且不能增删改内容,强行加标题违反规则4。所以只用

    和。 - 列表内容用