It is proved that a separable Fréchet space is quasinormable if, and only if, every quotient space satisfies the density condition of Heinrich. This answers positively a conjecture of Bonet and Dí az in the class of separable Fréchet spaces.
Dipartimento di Matematica, Università di Lecce, C.P. 193, Via per Arnesano, 73100 Lecce, Italy
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