Petitions can carry more weight when they are part of a personalized effort including other forms of appeal, particularly:
- Phone calls
You could provide the community (here on MO, and on the AT list, and at SBS) the address and phone number of a key decision maker or administrative body in this process (or more than one). If that person begins receiving letters and calls from faculty at numerous international universities, I suspect it would make a strong impression. In particular it might make the number of signatures on the online petition more real and harder to ignore. Also, getting even a few people in the Netherlands (pure mathematicians, applied mathematicians, physicists, and others) to go and visit the relevant administrators in person could be extremely effective.
You can find a reporter at De Telegraaf to write and publish a story about the VU's threat to close down the pure mathematics section and on the international uproar over this threat. If the decision makers see a public article exposing the ongoing damage to the international reputation of VU as a result of their proposal, it will become harder for them to argue that this action is in the best interest of the university and could prompt a rapid reconsideration. Similarly you could have an article in the Chronicle of Higher Education, either as a pure news story about the threat and the online response, or as a discussion piece about the state of the tenure system in the Netherlands.
Another source of support:
You could contact alumni of the VU mathematics department and have them write letters to the administrators communicating both how important the department was in their lives and how disappointed and disgruntled they would be to see the department decimated. If they are donors to the university, they could also indicate that the outcome of this decision will affect, in addition, their future contributions.
Another avenue to consider:
- Alternative funding options
You could bring forward alternative proposals to directly cover some of the budget gaps that are being `addressed' by the proposed measure. These could involve temporary distributed pay cuts to existing faculty and staff, along with fundraising efforts, or perhaps corporate donations or partnerships and other less traditional means. Even if some of the proposals are not appropriate in the end, an effort to contribute to the solution of the administration's funding problem might make them more receptive to revising their overall plan.