Original post is in here.
Motivation of this work was to make more fast, light prover and to reduce the verification cost using aggregation technique. Recursion & aggregation for zkSNARK proof system has been developed by several people, and shown that it has large recursion overhead. It requires the expensive pairing check inside the circuit, and also too many non-native field arithmetic inside the circuit. Some people have proven that the recursion & aggregation for zkSTARK is quite really fast, as zkSTARK operates on a single finite field, and does not require pairing.(instead a lot of hashing) We can make faster and lighter prover and aggregate multiple proofs cheaply with zkSTARK technology. zkSTARK has very fast proving time, it has a drawback that its proof size is too-large to be verified on-chain. This is where zkSNARK comes in. If we can prove the verification of zkSTARK proof inside zkSNARK circuit, the resulting proof will be much smaller and can be verified on-chain! It seems that we can obtain really nice proof system by combining them. Let's see more closely.