fayllar.orgma'muriyatiga murojaat qiling
R12..n(AiAj)=R12..n(Ai)R1..n(Aj),
R1..n(AiVAj)=R1..n(Ai)VR1..n(Aj),
R1..n(AiAj)=R1..n(Ai)R1..n(Aj),