15. A computer program product for generating a multi-document summary, the computer program product comprising: one or more computer-readable tangible storage media and program instructions stored on at least one of the one or more tangible storage media, the program instructions executable by a processor of a computer to perform a method, the method comprising: receiving a query statement, one or more documents, one or more summary constraints, and one or more goals; identifying one or more keywords within the query statement; performing a sentence selection from the one or more documents based on the one or more identified keywords; generating a plurality of candidate summaries of the one or more documents based on the performed sentence selection, the one or more goals, and a fully-polynomial randomized approximation scheme (FPRAS) cross entropy method; calculating a quality score for each of the plurality of generated candidate summaries using a plurality of quality features; and selecting a candidate summary from the plurality of generated candidate summaries with the highest calculated quality score that also satisfies a quality score threshold.
15. A computer program product for generating a multi-document summary, the computer program product comprising: one or more computer-readable tangible storage media and program instructions stored on at least one of the one or more tangible storage media, the program instructions executable by a processor of a computer to perform a method, the method comprising: receiving a query statement, one or more documents, one or more summary constraints, and one or more goals; identifying one or more keywords within the query statement; performing a sentence selection from the one or more documents based on the one or more identified keywords; generating a plurality of candidate summaries of the one or more documents based on the performed sentence selection, the one or more goals, and a fully-polynomial randomized approximation scheme (FPRAS) cross entropy method; calculating a quality score for each of the plurality of generated candidate summaries using a plurality of quality features; and selecting a candidate summary from the plurality of generated candidate summaries with the highest calculated quality score that also satisfies a quality score threshold. 16. The computer program product of claim 15 , further comprising: generating an expanded query statement using a plurality of query expansion techniques, wherein the expanded query statement comprises the one or more identified keywords and one or more other keywords related to the received query statement, and wherein the expanded query statement is used in the sentence selection.