sentences:  formula_1 has a primitive concept of quasi-cardinal, governed by eight additional axioms, intuitively standing for the quantity of objects in a collection.The quasi-cardinal of a quasi-set is not defined in the usual sense (by means of ordinals) because the "m"-atoms are assumed (absolutely) indistinguishable.Furthermore, it is possible to define a translation from the language of ZFU into the language of formula_1 in such a way so that there is a 'copy' of ZFU in formula_1.