Let <InlineEquation ID="IEq1270"> <EquationSource Format="TEX">$$\mathbb{M}_{m,n}$$</EquationSource> <EquationSource Format="MATHML"> <math xmlns:xlink="http://www.w3.org/1999/xlink"> <msub> <mi mathvariant="double-struck">M</mi> <mrow> <mi>m</mi> <mo>,</mo> <mi>n</mi> </mrow> </msub> </math> </EquationSource> </InlineEquation> be the linear space of real matrices of dimension m × n. A variational problem that arises quite often in applications is that of minimizing a real-valued function f on some feasible set <InlineEquation ID="IEq128"> <EquationSource Format="TEX">$$\Upomega\subseteq \mathbb{M}_{m,n}.$$</EquationSource> <EquationSource Format="MATHML"> <math xmlns:xlink="http://www.w3.org/1999/xlink"> <mrow> <mi mathvariant="normal">Ω</mi> <mo>⊆</mo> <msub> <mi mathvariant="double-struck">M</mi> <mrow> <mi>m</mi> <mo>,</mo> <mi>n</mi> </mrow> </msub>...</mo></mrow></math></equationsource></equationsource></inlineequation></equationsource></equationsource></inlineequation>

As a result of increased mobility patterns of workers, explaining labor flows and partitioning regions into local labor markets (LLMs) have become important economic issues. For the former, it is useful to understand jointly where individuals live and where they work. For the latter, such...