Original title: Nash-Bargaining HalpernSGD via Limited-Memory MultiLRSGA: A Two-Phase Optimizer for Multi-Objective Learning
Katherine Rossella Foglia, Francesco Sergio Pisani, Vittorio Colao · September 2026
Training artificial intelligence on several competing goals at once is tricky because improving one goal can worsen another. To solve this, researchers built a two-phase system called NB-HalpernSGDAn optimization algorithm that uses anchoring to improve convergence in stochastic settings. via LM-MultiLRSGAAn optimizer for multiple objectives that uses limited memory and rotational adjustments.. First, the system treats the goals like players in a game. It uses a memory-saving method called LM-MultiLRSGA, which keeps an important rotational correction tool, to find a balanced compromise called a Nash equilibriumA state in a competitive game where no player can gain by changing their strategy alone.. Second, the system uses that balance as a starting anchor to make the goals bargain with each other. It solves this bargaining step using a technique called HalpernSGD to reach a fair, shared solution. Tested on a physics-informed neural network model, this two-step approach beat established methods like PCGrad, MultiAdam, and DualConeGD.
Imagine preparing a meal for friends with different food preferences. Some want spicy, others mild, and you need a single dish that works for all. It's tricky because adding spice for one group makes it worse for another. In this paper, the method first lets each preference compete to find a balance where no one is too unhappy. Then, it uses that balance as a starting point to bargain towards a dish that makes everyone as satisfied as possible.
In machine learning, models often have to balance multiple competing goals, like accuracy and energy use. This method provides a better way to find compromises, helping researchers build more efficient and balanced systems. It outperforms existing approaches on a test model, showing practical improvement.
The method is validated only on a PINN-inspired neural model, so it may not generalize to all multi-objective problems. The convergence properties of the new phase are discussed, but not extensively proven as for HalpernSGD.
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Nash-Bargaining HalpernSGD via Limited-Memory MultiLRSGA: A Two-Phase Optimizer for Multi-Objective Learning — Katherine Rossella Foglia, Francesco Sergio Pisani, Vittorio Colao
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.