Cynthia Nixon, whose run for governor of New York is staked on her experience as an activist in the public schools, released her education platform on Wednesday. It outlined her vision for schools in the state, and highlighted differences with her opponent in the Democratic primary, Gov. Andrew M. Cuomo.

The $7.4 billion plan is ambitious, progressive — and expensive. Ms. Nixon proposes a $700 million expansion of child care subsidies and a new program to pay for college. She calls for more access to social services outside the classroom. And she sharply criticizes the status quo as a system where “white, wealthy children are prepared for college, and low-income children of color are disproportionately put into the school-to-prison pipeline.”

Positioning herself against Mr. Cuomo is a constant.

“If I had to attribute the fact that I’m running for governor to one issue and one moment,” Ms. Nixon said in an interview, “it would be the education issue.”

The biggest item on her agenda is $4.2 billion in additional money for K-12 education. Ms. Nixon favors a school funding formula called Foundation Aid, which was created after New York’s Court of Appeals found the state was not giving New York City enough money to provide its students with a “sound basic education” in 2006. The State Legislature and Gov. Eliot Spitzer wrote the Foundation Aid formula in response.