let x1, x2, x3, x4, x5, x6, y1, y2, y3, y4, y5, y6 be set ; :: thesis: ( [x1,x2,x3,x4,x5,x6] = [y1,y2,y3,y4,y5,y6] implies ( x1 = y1 & x2 = y2 & x3 = y3 & x4 = y4 & x5 = y5 & x6 = y6 ) )
assume A1: [x1,x2,x3,x4,x5,x6] = [y1,y2,y3,y4,y5,y6] ; :: thesis: ( x1 = y1 & x2 = y2 & x3 = y3 & x4 = y4 & x5 = y5 & x6 = y6 )
then [x1,x2,x3,x4,x5] = [y1,y2,y3,y4,y5] by ZFMISC_1:27;
hence ( x1 = y1 & x2 = y2 & x3 = y3 & x4 = y4 & x5 = y5 & x6 = y6 ) by A1, Th7, ZFMISC_1:27; :: thesis: verum