Ideal balanced pairs in extriangulated categories

Let C =(C, E, s) be an extriangulated category. In this paper, we give the notion of ideal balanced pairs in C and some equivalent characterizations of ideal balanced pairs. We show that there is a one-to-one correspondence between balanced pairs and ideal balanced pairs satisfying certain conditions when C is of a negative first extension. We also prove that there is a bijective correspondence between ideal balanced pairs(I, J) and additive subfunctors F ? E with enough projective morphisms and enough injective morphisms in C.