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	<id>https://sublinear.info/index.php?action=history&amp;feed=atom&amp;title=Open_Problems%3A94</id>
	<title>Open Problems:94 - Revision history</title>
	<link rel="self" type="application/atom+xml" href="https://sublinear.info/index.php?action=history&amp;feed=atom&amp;title=Open_Problems%3A94"/>
	<link rel="alternate" type="text/html" href="https://sublinear.info/index.php?title=Open_Problems:94&amp;action=history"/>
	<updated>2026-06-06T20:46:12Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
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	<entry>
		<id>https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1284&amp;oldid=prev</id>
		<title>Krzysztof Onak at 03:12, 25 August 2019</title>
		<link rel="alternate" type="text/html" href="https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1284&amp;oldid=prev"/>
		<updated>2019-08-25T03:12:41Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;Revision as of 03:12, 25 August 2019&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l2&quot; &gt;Line 2:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 2:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|source=warwick18&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|source=warwick18&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;}}&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;}}&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;1. Consider the problem of reporting statistics about online ads to the advertisers that pay for them. Advertisers may wish to know how many unique people matching some demographic conditions have seen an ad at a particular time range. There are many ads and many demographic conditions and time ranges; and the service provider should be able to accurately answer any possible query over ads, demographics, and time. In other words, it’s an [https://en.wikipedia.org/wiki/OLAP_cube OLAP cube] problem where the aggregate is ''distinct count'' rather than ''sum''.&amp;#160; How can one construct a sketch that will provide estimates with &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot;&lt;/del&gt;good&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot; &lt;/del&gt;errors that solves this with, say, $O(1)$ time complexity per query? Loosely speaking, &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot;&lt;/del&gt;good&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot; &lt;/del&gt;here means every query for an ad (without demographic conditions) has good relative error and any query that has a high count should have good relative error. &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;1. Consider the problem of reporting statistics about online ads to the advertisers that pay for them. Advertisers may wish to know how many unique people matching some demographic conditions have seen an ad at a particular time range. There are many ads and many demographic conditions and time ranges; and the service provider should be able to accurately answer any possible query over ads, demographics, and time. In other words, it’s an [https://en.wikipedia.org/wiki/OLAP_cube OLAP cube] problem where the aggregate is ''distinct count'' rather than ''sum''.&amp;#160; How can one construct a sketch that will provide estimates with &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;amp;ldquo;&lt;/ins&gt;good&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;amp;rdquo; &lt;/ins&gt;errors that solves this with, say, $O(1)$ time complexity per query? Loosely speaking, &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;amp;ldquo;&lt;/ins&gt;good&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;amp;rdquo; &lt;/ins&gt;here means every query for an ad (without demographic conditions) has good relative error and any query that has a high count should have good relative error. &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;2. Suppose a company tracks an important high level metric &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;''&lt;/del&gt;(e.g., total network traffic)&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;'' &lt;/del&gt;that is the sum of a metric over many discrete categories &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;''&lt;/del&gt;(e.g., country, device, network provider, etc.)&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;''&lt;/del&gt;. When that metric changes in an unexpected way, it wishes to figure out what combinations of categories are driving that change. How can one find a small set of&amp;#160; combination of categories that explains most of the change and can be described succinctly? Can this be done in real-time so that a streaming sketch can keep track of the appropriate approximate aggregates and the search for a succinct description of category can be done in &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot;&lt;/del&gt;reasonable&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot; &lt;/del&gt;time?&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;2. Suppose a company tracks an important high level metric (e.g., total network traffic) that is the sum of a metric over many discrete categories (e.g., country, device, network provider, etc.). When that metric changes in an unexpected way, it wishes to figure out what combinations of categories are driving that change. How can one find a small set of&amp;#160; combination of categories that explains most of the change and can be described succinctly? Can this be done in real-time so that a streaming sketch can keep track of the appropriate approximate aggregates and the search for a succinct description of category can be done in &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;amp;ldquo;&lt;/ins&gt;reasonable&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;amp;rdquo; &lt;/ins&gt;time?&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Krzysztof Onak</name></author>
		
	</entry>
	<entry>
		<id>https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1265&amp;oldid=prev</id>
		<title>Krzysztof Onak: Krzysztof Onak moved page Waiting:Ads Impressions and Statistics to Open Problems:94 without leaving a redirect</title>
		<link rel="alternate" type="text/html" href="https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1265&amp;oldid=prev"/>
		<updated>2019-08-20T03:53:24Z</updated>

		<summary type="html">&lt;p&gt;Krzysztof Onak moved page &lt;a href=&quot;/index.php?title=Waiting:Ads_Impressions_and_Statistics&amp;amp;action=edit&amp;amp;redlink=1&quot; class=&quot;new&quot; title=&quot;Waiting:Ads Impressions and Statistics (page does not exist)&quot;&gt;Waiting:Ads Impressions and Statistics&lt;/a&gt; to &lt;a href=&quot;/index.php?title=Open_Problems:94&quot; title=&quot;Open Problems:94&quot;&gt;Open Problems:94&lt;/a&gt; without leaving a redirect&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;1&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;1&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;Revision as of 03:53, 20 August 2019&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-notice&quot; lang=&quot;en&quot;&gt;&lt;div class=&quot;mw-diff-empty&quot;&gt;(No difference)&lt;/div&gt;
&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;</summary>
		<author><name>Krzysztof Onak</name></author>
		
	</entry>
	<entry>
		<id>https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1264&amp;oldid=prev</id>
		<title>Krzysztof Onak: Updating the header</title>
		<link rel="alternate" type="text/html" href="https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1264&amp;oldid=prev"/>
		<updated>2019-08-20T03:53:10Z</updated>

		<summary type="html">&lt;p&gt;Updating the header&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;Revision as of 03:53, 20 August 2019&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l1&quot; &gt;Line 1:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{{Header&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{{Header&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;|title=Ads, Impressions, and Statistics&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|source=warwick18&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|source=warwick18&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;}}&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;}}&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;1. Consider the problem of reporting statistics about online ads to the advertisers that pay for them. Advertisers may wish to know how many unique people matching some demographic conditions have seen an ad at a particular time range. There are many ads and many demographic conditions and time ranges; and the service provider should be able to accurately answer any possible query over ads, demographics, and time. In other words, it’s an [https://en.wikipedia.org/wiki/OLAP_cube OLAP cube] problem where the aggregate is ''distinct count'' rather than ''sum''.&amp;#160; How can one construct a sketch that will provide estimates with &amp;quot;good&amp;quot; errors that solves this with, say, $O(1)$ time complexity per query? Loosely speaking, &amp;quot;good&amp;quot; here means every query for an ad (without demographic conditions) has good relative error and any query that has a high count should have good relative error. &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;1. Consider the problem of reporting statistics about online ads to the advertisers that pay for them. Advertisers may wish to know how many unique people matching some demographic conditions have seen an ad at a particular time range. There are many ads and many demographic conditions and time ranges; and the service provider should be able to accurately answer any possible query over ads, demographics, and time. In other words, it’s an [https://en.wikipedia.org/wiki/OLAP_cube OLAP cube] problem where the aggregate is ''distinct count'' rather than ''sum''.&amp;#160; How can one construct a sketch that will provide estimates with &amp;quot;good&amp;quot; errors that solves this with, say, $O(1)$ time complexity per query? Loosely speaking, &amp;quot;good&amp;quot; here means every query for an ad (without demographic conditions) has good relative error and any query that has a high count should have good relative error. &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;2. Suppose a company tracks an important high level metric ''(e.g., total network traffic)'' that is the sum of a metric over many discrete categories ''(e.g., country, device, network provider, etc.)''. When that metric changes in an unexpected way, it wishes to figure out what combinations of categories are driving that change. How can one find a small set of&amp;#160; combination of categories that explains most of the change and can be described succinctly? Can this be done in real-time so that a streaming sketch can keep track of the appropriate approximate aggregates and the search for a succinct description of category can be done in &amp;quot;reasonable&amp;quot; time?&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;2. Suppose a company tracks an important high level metric ''(e.g., total network traffic)'' that is the sum of a metric over many discrete categories ''(e.g., country, device, network provider, etc.)''. When that metric changes in an unexpected way, it wishes to figure out what combinations of categories are driving that change. How can one find a small set of&amp;#160; combination of categories that explains most of the change and can be described succinctly? Can this be done in real-time so that a streaming sketch can keep track of the appropriate approximate aggregates and the search for a succinct description of category can be done in &amp;quot;reasonable&amp;quot; time?&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Krzysztof Onak</name></author>
		
	</entry>
	<entry>
		<id>https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1252&amp;oldid=prev</id>
		<title>Ccanonne at 22:13, 7 August 2019</title>
		<link rel="alternate" type="text/html" href="https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1252&amp;oldid=prev"/>
		<updated>2019-08-07T22:13:25Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;Revision as of 22:13, 7 August 2019&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l1&quot; &gt;Line 1:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{{Header&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{{Header&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|title=Ads, Impressions, and Statistics&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;&amp;amp;action=submit&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|title=Ads, Impressions, and Statistics&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|source=warwick18&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|source=warwick18&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;}}&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;}}&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;1. Consider the problem of reporting statistics about online ads to the advertisers that pay for them. Advertisers may wish to know how many unique people matching some demographic conditions have seen an ad at a particular time range. There are many ads and many demographic conditions and time ranges; and the service provider should be able to accurately answer any possible query over ads, demographics, and time. In other words, it’s an [https://en.wikipedia.org/wiki/OLAP_cube OLAP cube] problem where the aggregate is ''distinct count'' rather than ''sum''.&amp;#160; How can one construct a sketch that will provide estimates with &amp;quot;good&amp;quot; errors that solves this with, say, $O(1)$ time complexity per query? Loosely speaking, &amp;quot;good&amp;quot; here means every query for an ad (without demographic conditions) has good relative error and any query that has a high count should have good relative error. &lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;1. Consider the problem of reporting statistics about online ads to the advertisers that pay for them. Advertisers may wish to know how many unique people matching some demographic conditions have seen an ad at a particular time range. There are many ads and many demographic conditions and time ranges; and the service provider should be able to accurately answer any possible query over ads, demographics, and time. In other words, it’s an OLAP cube problem where the aggregate is ''distinct count'' rather than ''sum''.&amp;#160; How can one construct a sketch that will provide estimates with &amp;quot;good&amp;quot; errors that solves this with, say, $O(1)$ time complexity per query? Loosely speaking, &amp;quot;good&amp;quot; here means every query for an ad (without demographic conditions) has good relative error and any query that has a high count should have good relative error. &lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;2. Suppose a company tracks an important high level metric &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;''&lt;/ins&gt;(e.g.&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;, total &lt;/ins&gt;network traffic)&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;'' &lt;/ins&gt;that is the sum of a metric over many discrete categories &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;''&lt;/ins&gt;(e.g., country, device, network provider, etc.)&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;''&lt;/ins&gt;. When that metric changes in an unexpected way, it wishes to figure out what combinations of categories are driving that change. How can one find a small set of&amp;#160; combination of categories that explains most of the change and can be described succinctly? Can this be done in real-time so that a streaming sketch can keep track of the appropriate approximate aggregates and the search for a succinct description of category can be done in &amp;quot;reasonable&amp;quot; time?&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;2. Suppose a company tracks an important high level metric (e.g. &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;Total &lt;/del&gt;network traffic) that is the sum of a metric over many discrete categories (e.g., country, device, network provider, etc.). When that metric changes in an unexpected way, it wishes to figure out what combinations of categories are driving that change. How can one find a small set of&amp;#160; combination of categories that explains most of the change and can be described succinctly? Can this be done in real-time so that a streaming sketch can keep track of the appropriate approximate aggregates and the search for a succinct description of category can be done in &amp;quot;reasonable&amp;quot; time?&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Ccanonne</name></author>
		
	</entry>
	<entry>
		<id>https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1251&amp;oldid=prev</id>
		<title>Ccanonne: Created page with &quot;{{Header |title=Ads, Impressions, and Statistics&amp;action=submit |source=warwick18 }}   1. Consider the problem of reporting statistics about online ads to the advertisers that...&quot;</title>
		<link rel="alternate" type="text/html" href="https://sublinear.info/index.php?title=Open_Problems:94&amp;diff=1251&amp;oldid=prev"/>
		<updated>2019-08-07T22:11:19Z</updated>

		<summary type="html">&lt;p&gt;Created page with &amp;quot;{{Header |title=Ads, Impressions, and Statistics&amp;amp;action=submit |source=warwick18 }}   1. Consider the problem of reporting statistics about online ads to the advertisers that...&amp;quot;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;{{Header&lt;br /&gt;
|title=Ads, Impressions, and Statistics&amp;amp;action=submit&lt;br /&gt;
|source=warwick18&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
1. Consider the problem of reporting statistics about online ads to the advertisers that pay for them. Advertisers may wish to know how many unique people matching some demographic conditions have seen an ad at a particular time range. There are many ads and many demographic conditions and time ranges; and the service provider should be able to accurately answer any possible query over ads, demographics, and time. In other words, it’s an OLAP cube problem where the aggregate is ''distinct count'' rather than ''sum''.  How can one construct a sketch that will provide estimates with &amp;quot;good&amp;quot; errors that solves this with, say, $O(1)$ time complexity per query? Loosely speaking, &amp;quot;good&amp;quot; here means every query for an ad (without demographic conditions) has good relative error and any query that has a high count should have good relative error. &lt;br /&gt;
&lt;br /&gt;
2. Suppose a company tracks an important high level metric (e.g. Total network traffic) that is the sum of a metric over many discrete categories (e.g., country, device, network provider, etc.). When that metric changes in an unexpected way, it wishes to figure out what combinations of categories are driving that change. How can one find a small set of  combination of categories that explains most of the change and can be described succinctly? Can this be done in real-time so that a streaming sketch can keep track of the appropriate approximate aggregates and the search for a succinct description of category can be done in &amp;quot;reasonable&amp;quot; time?&lt;/div&gt;</summary>
		<author><name>Ccanonne</name></author>
		
	</entry>
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