2026-08-28·by Sijie Wang#idea#optimization#math

modern-frontier

Parent: optimization

Where the objective itself is learned, adversarial, nested, or over distributions.

Bilevel & meta-optimization

  • An optimization inside an optimization: hyperparameter optimization, learning-to-optimize (learn the update rule), meta-learning (MAML);
  • "LLMs as optimizers" (OPRO) — the model proposes/refines solutions; in-context learning ≈ implicit gradient descent. → our LLM-as-inner-optimizer (stages-gates-as-hard-optimization).

Minimax / games / adversarial

  • Saddle-point problems min_x max_y f(x,y): GANs, adversarial training, robust optimization;
  • Solved by no-regret dynamics / gradient-descent-ascent / monotone operators; convergence is subtle (cycling, not descent).

Optimal transport & gradient flows on measures

  • Optimal transport / Wasserstein distance; optimizing over probability distributions;
  • Wasserstein gradient flows = PDEs on measure space (Fokker–Planck) — the math under diffusion models.

Structuring hard optimization (the continuation family)

  • Homotopy / continuation, graduated non-convexity, curriculum learning, annealing — solve a path of easy→hard problems, each warm-starting the next.
  • → this is stages-and-gates: stages-gates-as-hard-optimization.

The unifying abstractions

  • Monotone operators / fixed-point theory — GD, proximal, ADMM, primal-dual all as fixed-point iterations of (firmly) nonexpansive operators;
  • Everything is: iterate an operator to its fixed point; converges iff it's a contraction / the flow is stabledynamics-to-a-fixed-point.

The theme

The clean "minimize a fixed convex f" dissolves: the objective is learned (bilevel), adversarial (minimax), over distributions (OT), or too hard to descend directly (continuation). This frontier is exactly where the agent/LLM optimization thread sits.

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