Let S be the set of all strings from A* in which there is no b before an a. For example, the strings λ, aa, bbb, and aa all belong to S, but aabab ∉ S. Give a recursive definition for the set S. (Hint: a recursive rule can concatenate characters at the beginning or the end of a string.)

How can i clip a picture to a question on the computer?

Acomputer has a two-level cache. suppose that 60% of the memory references hit on the first level cache, 35% hit on the second level, and 5% miss. the access times are 5 nsec, 15 nsec, and 60 nsec, respectively, where the times for the level 2 cache and memory start counting at the moment it is known that they are needed (e. g., a level 2 cache access does not even start until the level 1 cache miss occurs). what is the average access time?

Which of these is a benefit of using objects in a powerpoint presentation? a. collaborators can create the external files while you create and edit the slide show. b. you can easily change the theme and design of the presentation. c. you can have older data in the source file while having up-to-date data in the presentation. d. collaborators can easily share the presentation.