Abstract The article is motivated by the recently published studies on injective and projective hypermodules. We present here a new characterization of normal First we define concept zero-divisors over hypermodule based it introduce class hypermodules, one divisible After presenting some their fundamental properties, will show that R -hypermodules M coincide whenever hyperring with no . Finally...

Efficient evaluation of user queries is very important and critical in database applications involving very large amount of data. In these applications, especially the ones where query answers are expected in real time, performance of query evaluation in a DBMS may be poor; often in such cases, query performance is extremely sensitive to the structure of the database schema. For example, if a q...

We introduce joins of signed graphs and explore the chromatic number all-positive all-negative joins. prove an analogue to theorem that join two equals sum their numbers. Given graphs, is usually less than numbers, by amount depends on new concept deficiency a signed-graph coloration.