Update lookups.md

tweaks for clarity

book/src/how/lookups.md

@@ -1,8 +1,8 @@
 # Lookups
-Lasso is a lookup argument. Lookup arguments allow the prover to convince the verifier that a set of values $Q$ is a subset of a lookup table $T$. Lasso is a special lookup argument with highly desirable asymptotic costs largely correlated to the number of queries $Q$ rather than the length of of the table $T$.
+Lasso is a lookup argument (equivalent to a SNARK for reads into a read-only memory). Lookup arguments allow the prover to convince the verifier that a (committed) set of values $Q$ is a subset of a lookup table $T$. Lasso is a special lookup argument with highly desirable asymptotic costs largely correlated to the number of queries $Q$ rather than the length of of the table $T$.
 
 A conversational background on lookups can be found [here](https://a16zcrypto.com/posts/article/building-on-lasso-and-jolt/). In short: Lookups are great for zkVMs as they allow constant cost / developer complexity for the prover algorithm per VM instruction.
 
 ## Lasso
 A detailed engineering overview of Lasso can be found [here](https://www.youtube.com/watch?v=iDcXj9Vx3zY).
-![Lasso SVG](../imgs/lasso.svg)
+![Lasso SVG](../imgs/lasso.svg)