If you are an eligible student, postdoctoral researcher, or scientist, please write petsc-maint@mcs.anl.gov (the private list) briefly explaining your situation and expertise. They will try to match you with a host. You may also write a potential host directly and write us jointly.
If you are at a European university and willing to host an impacted student, postdoctoral researcher, or scientist from Ukraine to work on PETSc, please rsend an email to petsc-maint@mcs.anl.gov briefly describing your area.
Or contact the PERMON Team leader David Horák david.horak@vsb.cz who can be your host at VSB.
Details are attached in the letter.