Abstract: I will talk about the BPS nature of the decoupling limits that lead to matrix theories on D-branes, and their relations to the AdS/CFT correspondence. From this BPS perspective, I will then conjecture that a DLCQ^n/DLCQ^m correspondence, with m > n, captures the notion of holography in string theory. Here, DLCQ is short for Discrete Light Cone Quantization, which is a nonperturbative approach to quantum field theories and string/M-theory. Finally, I will show that the bulk geometry is generated via a deformation dual to the TTbar, which offsets the difference between the exponents n and m in the DLCQ^n/DLCQ^m correspondence.