Mathematics has a dependency graph
Most math education ignores this. Brilliant does. Lemma makes it the whole product.
Every concept knows what it depends on
Lemma doesn't have courses. It has nodes. Every math concept connects to the ones that come before it. You pick a destination — "understand backpropagation" — and Lemma finds the shortest path from what you already know.
Foundations → Algebra → Geometry → Trig → Calculus → Linear Algebra → ML Math
Same proof, seven different explanations. You read it in the voice that makes it click.
Each node tracks your mastery score — up when you get problems right (more if you didn't peek at the hints), drifting down over time until you review. Lemma surfaces what's due before you forget it.
Ace the easy ones and it pushes harder. Miss a couple and it backs off. Spaced repetition, automatic.
One price. Your终身.
No subscription. No "subscribe to access." You pay once, you get everything — every concept, every voice, every widget, every future node we add.
Free tier: browse the graph, read the first few lessons. That's it. Pay once, and the whole thing opens up.
"Every student who has ever failed calculus wasn't bad at calculus.
They were missing a prerequisite three steps back."
— The insight that broke education, and the one Lemma is built on