The phrase "a solid problem" is correct and usable in written English.
It can be used to describe a problem that is well-defined, significant, or worthy of attention in a particular context.
Example: "The team faced a solid problem that required innovative solutions to overcome the challenges presented by the new project."
Alternatives: "a substantial issue" or "a significant challenge".
More impressively, in a different text from this same period, Descartes offers a method for constructing all solid problems, i.e., for solving all third- and fourth-degree equations.
A solid transportation problem can be converted to a classical transportation problem by considering only a single type of conveyance.
This implementation employs a fixed mesh for the solution of the fluid problem and a Lagrangian formulation for the solid problem.
For example, Bit et al. [4] used a fuzzy programming approach to solve a MOSTP; Ida et al. [5] presented a neural network method to solve a MOSTP; Gao and Liu [6] developed two-phase fuzzy algorithms to solve multi-objective STP; Tao and Xu [7] developed a class of rough multiple objective programming and its application to a solid transportation problem.
The idea is to solve the full 3D solid problem separating the in-plane and the out-of-plane spaces.
By using a mixed Lagrange Euler approach in model derivation, the solid continuum problem can be transformed into a solid continuum flow problem.
No cod science, no pretence of lasting change, just solid problem-solving for when one's face looks like an old slipper.
This suggests an important overlap between Descartes' three classes of geometrical problems and Pappus's three classes, which, recall, were separated based on the types of curves required for solution: Planar problems are solvable by straightedge and compass, solid problems by conics, and line-like problems by more complicated curves that have an "inconstant and changeable origin".
DPSM results for a solid half-space problem are compared with the finite element predictions to show the superiority of the DPSM technique.
