DLV ASCII

Consider a geographical database $($see geo. db in Files$/$Programs$/).$ Note that DLV can be provided with multiple input files so you can write your solution in a separate file and feed both files to DLV on the command line. The command line switch $"-$nofacts" will omit printing the entire database every time. The database has the schema listed below $($essentially$,$ each predicate is a table in a relational database$)$

state$($name$,$ abbreviation, captial, population, area, orderJoinedUSA,

largestcity, secondlargest$,$ third, fourth$)$

city$($state$,$ stateabbrev, name, population$)$

river$($riverName$,$ length$)$

riverin$($riverName$,$ state$).$

borders$($state$,$ state$).$

highlow$($state$,$ abreviation, highPlace, height$1,$ lowPlace, height$2)$

mountain$($state$,$ abreviation, mountainName, height$)$

lake$($lakeName$,$ size$)$

lakein$($lakeName$,$ state$).$

road$($roadName$,$ state$).$

Answer the following database queries. One way to surface the answers easily is to write predicates like "part$4$a$($X$)$ :$-..."$ where you define the solution for that part.

$($a$)$ What are the names of rivers that run through Texas?

$($b$)$ Which lakes are in at least two different states?

$($c$)$ Two states are nearby if

$($i$)$ They share a border

$($ii$)$ They share a border with the same state

Find all the states nearby a state containing a city named Kansas City.

$($d$)$ A Symbolic Set in DLV is a syntactic construct $\{$ Variables : Conjunction$\}$ that creates a set of all variables that make the conjunction true. Much like in SQL$,$ you can apply aggregate functions find the #count, #sum, #times, #min, and #max of the

$($first$)$ variable in the Symbolic Set. For example:

answer $($C$)$ I$-$ C $-$ #oount$\{$N i riverin$($N$,$ "pennsylvanis"$),$ river $($N$,$L$),$ L$>1000\}.$

Counts the number of rivers in Pennsylvania that are longer than $1000$ miles long $($the answer is $1$ by the way$)."\{$N : riverin$($N$,$ "pennsylvania"$),$ river $($N$,$L$),$ L$>1000)"$ is a symbolic set representing all the values N that are the names of rivers in PA that are longer than $1000$ miles long, and #count says to count how many.

Find the number of states that border any state containing the shortest river.

$($e$)$ What is the most populous state with a mountain higher than $4000($meters$)?$

Note use dlv$.$mingw.exe in Windows to solve