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Nonlinear three-operator splitting algorithms with momentum for monotone inclusions

Liqian Qin, Aviv Gibali, Cuijie Zhang, Yuchao Tang

TL;DR

This work addresses monotone inclusion problems of the form $0 \in Ax+Bx+Cx$ by introducing three nonlinear momentum-augmented splitting schemes that leverage warped resolvents to exploit problem structure. The methods—nonlinear SFRBS, SRFBS, and ORFBS—are shown to converge weakly under standard assumptions, with $R$-linear convergence when $A$ is strongly monotone. The paper provides rigorous convergence analyses and linear rates, plus extensive numerical experiments on synthetic data and portfolio-optimization quadratic programs confirming faster convergence and robustness compared with existing schemes. These results broaden the toolbox for multi-operator splitting, enabling more efficient solutions for structured monotone inclusions and suggesting avenues for four-operator extensions.

Abstract

In this paper, we introduce three novel splitting algorithms for solving structured monotone inclusion problems involving the sum of a maximally monotone operator, a monotone and Lipschitz continuous operator and a cocoercive operator. Each proposed method extends one of the classical schemes: the semi-forward-reflected-backward splitting algorithm, the semi-reflected-forward-backward splitting algorithm, and the outer reflected forward-backward splitting algorithm by incorporating a nonlinear momentum term. Under appropriate step-size conditions, we establish the weak convergence of all three algorithms, and further prove their $R$-linear convergence rates under strong monotonicity assumptions. Preliminary numerical experiments on both synthetic datasets and real-world quadratic programming problems in portfolio optimization demonstrate the effectiveness and superiority of the proposed algorithms.

Nonlinear three-operator splitting algorithms with momentum for monotone inclusions

TL;DR

This work addresses monotone inclusion problems of the form by introducing three nonlinear momentum-augmented splitting schemes that leverage warped resolvents to exploit problem structure. The methods—nonlinear SFRBS, SRFBS, and ORFBS—are shown to converge weakly under standard assumptions, with -linear convergence when is strongly monotone. The paper provides rigorous convergence analyses and linear rates, plus extensive numerical experiments on synthetic data and portfolio-optimization quadratic programs confirming faster convergence and robustness compared with existing schemes. These results broaden the toolbox for multi-operator splitting, enabling more efficient solutions for structured monotone inclusions and suggesting avenues for four-operator extensions.

Abstract

In this paper, we introduce three novel splitting algorithms for solving structured monotone inclusion problems involving the sum of a maximally monotone operator, a monotone and Lipschitz continuous operator and a cocoercive operator. Each proposed method extends one of the classical schemes: the semi-forward-reflected-backward splitting algorithm, the semi-reflected-forward-backward splitting algorithm, and the outer reflected forward-backward splitting algorithm by incorporating a nonlinear momentum term. Under appropriate step-size conditions, we establish the weak convergence of all three algorithms, and further prove their -linear convergence rates under strong monotonicity assumptions. Preliminary numerical experiments on both synthetic datasets and real-world quadratic programming problems in portfolio optimization demonstrate the effectiveness and superiority of the proposed algorithms.

Paper Structure

This paper contains 13 sections, 13 theorems, 130 equations, 1 figure, 2 tables, 3 algorithms.

Key Result

Lemma 2.1

(Morin ) Let $C$ be the $\beta^{-1}$-cocoercive operator w.r.t. $S$, for some $\beta>0$. Then the following inequality holds:

Figures (1)

  • Figure 1: Portfolio optimization solutions for problem \ref{['portfolio-problem']}: ORFBS algorithm \ref{['ORFBS']} (top row) versus Algorithm \ref{['new-ORFBS']} (bottom row).

Theorems & Definitions (28)

  • Definition 2.1
  • Definition 2.2
  • Definition 2.3
  • Lemma 2.1
  • Lemma 2.2
  • Lemma 2.3
  • Proposition 3.1
  • Lemma 3.1
  • proof
  • Theorem 3.1
  • ...and 18 more