define matrix multiply

Signed-off-by: JIANG Di <dd19941105@gmail.com>
move b.c TransitiveBinaryRelation.c

Signed-off-by: JIANG Di <dd19941105@gmail.com>
mobe a.c, a.clj to SetOperation.c SetOperation.clj

Signed-off-by: JIANG Di <dd19941105@gmail.com>
it just works fun

Signed-off-by: JIANG Di <dd19941105@gmail.com>
add comment

Signed-off-by: JIANG Di <dd19941105@gmail.com>