%0 Journal Article %A Bluman, George W. %A Rosa Silva, Rafael de la %T The natural extension to PDEs of Lie's reduction of order algorithm for ODEs %D 2025 %@ 1007-5704 %U http://hdl.handle.net/10498/35481 %X n this paper, we further consider the symmetry-based method for seeking nonlocally related systems for partial differential equations. In particular, we show that the symmetry-based method for partial differential equations is the natural extension of Lie's reduction of order algorithm for ordinary differential equations by looking at this algorithm from a different point of view. Many examples exhibit various situations that can arise. %K Lie's reduction of order algorithm %K Nonlocal symmetries %K Nonlocally related systems %K Symmetry-based method %~ Universidad de Cádiz