PF: An applicant was on parental leave for 4,5 years but they kept a small part-time contract with their initial employer. Apart from this job, they also participated in research projects for different universities. What documents should the applicant provide as proof?

Having part-time contracts and participating in researcher projects does not look like a complete parental leave as the researcher was somewhat active in research during this period.

PF: What supporting documents are necessary to prove a period of parental leave?

The time researchers want deducted for parental leave is the official time they have taken for parental leave and it needs to be documented, with a certificate from the employer indicating this, together with Social Security documentation.