*Result*: Bilevel gradient methods and the Morse parametric qualification condition

Title:
Bilevel gradient methods and the Morse parametric qualification condition
Publication Year:
2025
Subject Terms:
Document Type:
*Report* Working Paper
Accession Number:
edsarx.2502.09074
Database:
arXiv

*Further Information*

*We introduce the Morse parametric qualification condition for bilevel programming. Generic semi-algebraic functions are Morse parametric in a piecewise sense. Thus, bilevel programs with a Morse parametric lower level constitute a relevant intermediate class between strongly convex and fully generic lower levels. In this framework, we study bilevel gradient algorithms with two strategies: the single-step multi-step strategy, which involves a sequence of steps on the lower-level problems followed by one step on the upper-level problem, and a differentiable programming strategy that optimizes a smooth approximation of the bilevel problem. While the first is shown to be a biased gradient method on the problem with rich properties, the second, inspired by meta-learning applications, is less stable but offers simplicity and ease of implementation.*