Constructivist and Structuralist Foundations: Bishop's and Lawvere's   Theories of Sets
  Bishop's informal set theory is briefly discussed and compared to Lawvere's Elementary Theory of the Category of Sets (ETCS). We then present a constructive and predicative version of ETCS, whose standard model is based on the constructive type theory of Martin-L\"of. The theory, CETCS, provides a structuralist foundation for constructive mathematics in the style of Bishop. 
Erik Palmgren
math.LO math.CT