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**ENRIQUESTEFANINI** Perhaps this is not the proper place but, nonetheless, there it goes: E, K are fields, K included in E. A is a subset of E and all elements of A are algebraic over K. And the author says: "Clearly K(A) is the union of all subfields of the form K(M), where M ranges over finite subsets of A".

It is this statement I cannot understand. I have proved that the union of the K(M) is included in K(A) but I cannot prove the inverse inclusion. Thank you for you time.

Enrique.