Coequalisers of formal topology

We give a predicative construction of quotients of formal topologies. Along with earlier results on the match up between of continuous functions on real numbers (in the sense of Bishop\u27s constructive mathematics) and approximable mappings on the formal space of reals, we argue that formal topology gives an adequate foundation for constructive algebraic topology, also in the predicative sense. Predicativity is of essence when formalising the subject in logical frameworks based on Martin-Löf type theories