Update OPEN_PROBLEMS/DECENTRALIZED_DATA_DELIVERY_MARKETS.md

Co-authored-by: Jorge Soares <[email protected]>

Author: 2 people

OPEN_PROBLEMS/DECENTRALIZED_DATA_DELIVERY_MARKETS.md

@@ -116,7 +116,7 @@ In review, the Metering & Fair Exchange fields end up contributing to each other
     *   How to verify that the provider has the ability to delivery the file (e.g. has a local copy or is able to pull it from the network)
     *   How to verify that the file being transferred is the one requested, before a large amount of resources has been invested (i.e. before the entirety of the file has been transmitted)
     *   How to verify that the client has received the file
-  *   How to verify and reward that SLA were guaranteed?
+  *   How to verify and reward that SLA were met?
   *   How to avoid collusion when adding a third-party (e.g. Referee)?
   *   How to avoid grieving attacks (make one party pay for fees)?
   *   How to avoid a malicious actor causing un-rewarded work, hence wasting the others’ resources?