So, without introducing a federal pension plan it should be possible to create co-operation by making pension payments transferable between public pensions  to facilitate working in different member states. I assume most public pensions works by withholding a part of your salary and your final pension depends somewhat on total amount withheld. Would transfers work, or is there a better mechanism?

Not that I am against a federal public pension plan, but I think under current management it is easier to get something by pushing for incremental improvement of existing national public pensions.

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