As California began sending ballots to 23 million registered voters on Oct. 5, supporters of a proposed billionaire tax were trying to make one instruction stick: vote Yes on Proposition 40, and No on Propositions 41 and 42. The measures are linked. Under the rules described by tax supporters, Proposition 40 survives only if it receives more votes than each of the other two measures. A stronger vote for either Proposition 41 or Proposition 42 would block it. At a summit on wealth and inequality held Monday at San Francisco’s Hibernia Bank building, the ballot sequence was a persistent worry, even among people who support the tax. Twenty-five attendees told Mission Local they were unsure voters had received the message. One participant suggested creating a memorable campaign jingle. Frank Jernigan, a retired Google millionaire and co-founder of the group Patriotic Millionaires, said he had been explaining the two “No” votes to people he met, but found that few already knew about them. Oakland musician Mistah F.A.B. had delivered the instructions in a rap at a Saturday rally featuring U.S. Sen. Bernie Sanders: “Yes on Prop. 40, no on 41 and 42.” The ballot measures are backed by opposing coalitions. Proposition 41 would bar new state taxes that leave revenue outside the state spending limit. Proposition 42 would prohibit new state personal-property taxes and certain retroactive state taxes. Opponents of Proposition 40 have supported the two measures as a way to defeat the wealth tax. Campaign finance filings cited at the summit showed Google co-founder Sergey Brin had spent $328 million to oppose Proposition 40 and support the other measures. SEIU-United Healthcare Workers West, which leads the coalition backing Proposition 40, had spent $38 million this year. Recent polling compiled by The New York Times showed general support for the tax, but most polls had it below 50 percent. The dispute has divided California Democrats. Gov. Gavin Newsom opposes the tax, warning that wealthy residents could leave the state and weaken revenues for public services, including schools. Xavier Becerra, a Democrat running for governor against Republican Steve Hilton in November, also opposes it. The San Francisco Democratic Party voted against the tax in August, breaking with the state party. At Monday’s event, U.S. Rep. Ro Khanna of San Jose criticized what he called California’s entrenched political machine, while discussing the influence of powerful political networks. Khanna has also challenged Newsom over his opposition to Proposition 40. For tax supporters, the ballot’s unusual structure adds a practical hurdle to a broader fight over who holds political and economic power. The summit, hosted by the group Excessive Wealth, brought together lawmakers, researchers, authors and wealthy advocates of redistribution. Organizers displayed a live tracker claiming that the world’s richest people had gained a combined $4 billion by the event’s sixth hour.