Browse/Search Machine
A search is a selection condition on the Web
- find all objects with value=“SGML”
- find all references with label “A”
Searches may produce infinite number of tuples
A browse/search machine has
- a browser machine (and controller)
- right-infinite search-answer tape
- search-condition tape
- when search state is reached, a search is triggered
- answers to previously triggered searches arrive to the search-answer tape at arbitrary times at arbitrary order
- the machine non-deterministically evaluates certain search conditions on a part of the web and writes the answers
- all answers to a search are eventually written to the tape