More and more arguments are being introduced, either congruently or interchangeably, into the list of criteria for the adoption of the common currency. Sometimes, preconceived positions make their way through the multitude of invoked counter-arguments. Nominal convergence criteria have been continuously supplemented, sometimes just in the vortex of the scientific debate, although the euro project transcends the (calculated) scientific framework, regardless of the degree of quantitative sophistication.

I did not intend to develop here and now a comprehensive analysis. Some of the arguments put forward already benefit from the necessary attention, despite some inadequacies in relation to the scientific criteria. Others would really merit the honest concern of the researcher, but without letting the numbers alter the stake of the visionary construction.

This text is devoted to inter-regional development gaps, often presented as real obstacles to the enlargement of the euro area to the south-east of the EU. In this respect, I considered that the dynamic image of the gaps between the regions of the EU countries is important, even if the outcome, whatever it may be, can not be decisive or edifying for the institutional path of the euro area.

In this respect, I highlighted the internal development gaps, the inter-regional ones, and I illustrated the dynamics of these gaps in the last decade and a half, which in fact incorporates the entire history of the common currency.