I have this confusion. Lets say I have two languages produced by type 3 grammar such that
L(G1) = <Vn1,Vt,P1,S1> L(G2) = <Vn2,Vt,P2,S2>
I need to find a type3 grammar G3 such that
L(G3) = L(G1)L(G2)
I can't use $S3 \rightarrow S1S2$ to get the concatenaion, because the production is not type 3 as well. So what should I do?