let K be non empty right_complementable Abelian add-associative right_zeroed associative well-unital distributive doubleLoopStr ; :: thesis: for V, W being VectSp of K
for f being bilinear-Form of V,W holds
( leftker (QForm f) = leftker (RQForm (LQForm f)) & rightker (QForm f) = rightker (RQForm (LQForm f)) & leftker (QForm f) = leftker (LQForm (RQForm f)) & rightker (QForm f) = rightker (LQForm (RQForm f)) )

let V, W be VectSp of K; :: thesis: for f being bilinear-Form of V,W holds
( leftker (QForm f) = leftker (RQForm (LQForm f)) & rightker (QForm f) = rightker (RQForm (LQForm f)) & leftker (QForm f) = leftker (LQForm (RQForm f)) & rightker (QForm f) = rightker (LQForm (RQForm f)) )

let f be bilinear-Form of V,W; :: thesis: ( leftker (QForm f) = leftker (RQForm (LQForm f)) & rightker (QForm f) = rightker (RQForm (LQForm f)) & leftker (QForm f) = leftker (LQForm (RQForm f)) & rightker (QForm f) = rightker (LQForm (RQForm f)) )
set vq = VectQuot V,(LKer f);
set wq = VectQuot W,(RKer f);
set wqr = VectQuot W,(RKer (LQForm f));
set vql = VectQuot V,(LKer (RQForm f));
set rlf = RQForm (LQForm f);
set qf = QForm f;
set lrf = LQForm (RQForm f);
thus leftker (QForm f) c= leftker (RQForm (LQForm f)) :: according to XBOOLE_0:def 10 :: thesis: ( leftker (RQForm (LQForm f)) c= leftker (QForm f) & rightker (QForm f) = rightker (RQForm (LQForm f)) & leftker (QForm f) = leftker (LQForm (RQForm f)) & rightker (QForm f) = rightker (LQForm (RQForm f)) )
proof
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in leftker (QForm f) or x in leftker (RQForm (LQForm f)) )
assume x in leftker (QForm f) ; :: thesis: x in leftker (RQForm (LQForm f))
then consider vv being Vector of (VectQuot V,(LKer f)) such that
A1: ( x = vv & ( for ww being Vector of (VectQuot W,(RKer f)) holds (QForm f) . vv,ww = 0. K ) ) ;
now
let ww be Vector of (VectQuot W,(RKer (LQForm f))); :: thesis: (RQForm (LQForm f)) . vv,ww = 0. K
reconsider w = ww as Vector of (VectQuot W,(RKer f)) by Th47;
thus (RQForm (LQForm f)) . vv,ww = (QForm f) . vv,w by Th49
.= 0. K by A1 ; :: thesis: verum
end;
hence x in leftker (RQForm (LQForm f)) by A1; :: thesis: verum
end;
thus leftker (RQForm (LQForm f)) c= leftker (QForm f) :: thesis: ( rightker (QForm f) = rightker (RQForm (LQForm f)) & leftker (QForm f) = leftker (LQForm (RQForm f)) & rightker (QForm f) = rightker (LQForm (RQForm f)) )
proof
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in leftker (RQForm (LQForm f)) or x in leftker (QForm f) )
assume x in leftker (RQForm (LQForm f)) ; :: thesis: x in leftker (QForm f)
then consider vv being Vector of (VectQuot V,(LKer f)) such that
A2: ( x = vv & ( for ww being Vector of (VectQuot W,(RKer (LQForm f))) holds (RQForm (LQForm f)) . vv,ww = 0. K ) ) ;
now
let ww be Vector of (VectQuot W,(RKer f)); :: thesis: (QForm f) . vv,ww = 0. K
reconsider w = ww as Vector of (VectQuot W,(RKer (LQForm f))) by Th47;
thus (QForm f) . vv,ww = (RQForm (LQForm f)) . vv,w by Th49
.= 0. K by A2 ; :: thesis: verum
end;
hence x in leftker (QForm f) by A2; :: thesis: verum
end;
thus rightker (QForm f) c= rightker (RQForm (LQForm f)) :: according to XBOOLE_0:def 10 :: thesis: ( rightker (RQForm (LQForm f)) c= rightker (QForm f) & leftker (QForm f) = leftker (LQForm (RQForm f)) & rightker (QForm f) = rightker (LQForm (RQForm f)) )
proof
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in rightker (QForm f) or x in rightker (RQForm (LQForm f)) )
assume x in rightker (QForm f) ; :: thesis: x in rightker (RQForm (LQForm f))
then consider ww being Vector of (VectQuot W,(RKer f)) such that
A3: ( x = ww & ( for vv being Vector of (VectQuot V,(LKer f)) holds (QForm f) . vv,ww = 0. K ) ) ;
reconsider w = ww as Vector of (VectQuot W,(RKer (LQForm f))) by Th47;
now
let vv be Vector of (VectQuot V,(LKer f)); :: thesis: (RQForm (LQForm f)) . vv,w = 0. K
thus (RQForm (LQForm f)) . vv,w = (QForm f) . vv,ww by Th49
.= 0. K by A3 ; :: thesis: verum
end;
hence x in rightker (RQForm (LQForm f)) by A3; :: thesis: verum
end;
thus rightker (RQForm (LQForm f)) c= rightker (QForm f) :: thesis: ( leftker (QForm f) = leftker (LQForm (RQForm f)) & rightker (QForm f) = rightker (LQForm (RQForm f)) )
proof
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in rightker (RQForm (LQForm f)) or x in rightker (QForm f) )
assume x in rightker (RQForm (LQForm f)) ; :: thesis: x in rightker (QForm f)
then consider ww being Vector of (VectQuot W,(RKer (LQForm f))) such that
A4: ( x = ww & ( for vv being Vector of (VectQuot V,(LKer f)) holds (RQForm (LQForm f)) . vv,ww = 0. K ) ) ;
reconsider w = ww as Vector of (VectQuot W,(RKer f)) by Th47;
now
let vv be Vector of (VectQuot V,(LKer f)); :: thesis: (QForm f) . vv,w = 0. K
thus (QForm f) . vv,w = (RQForm (LQForm f)) . vv,ww by Th49
.= 0. K by A4 ; :: thesis: verum
end;
hence x in rightker (QForm f) by A4; :: thesis: verum
end;
thus leftker (QForm f) c= leftker (LQForm (RQForm f)) :: according to XBOOLE_0:def 10 :: thesis: ( leftker (LQForm (RQForm f)) c= leftker (QForm f) & rightker (QForm f) = rightker (LQForm (RQForm f)) )
proof
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in leftker (QForm f) or x in leftker (LQForm (RQForm f)) )
assume x in leftker (QForm f) ; :: thesis: x in leftker (LQForm (RQForm f))
then consider vv being Vector of (VectQuot V,(LKer f)) such that
A5: ( x = vv & ( for ww being Vector of (VectQuot W,(RKer f)) holds (QForm f) . vv,ww = 0. K ) ) ;
reconsider v = vv as Vector of (VectQuot V,(LKer (RQForm f))) by Th48;
now
let ww be Vector of (VectQuot W,(RKer f)); :: thesis: (LQForm (RQForm f)) . v,ww = 0. K
thus (LQForm (RQForm f)) . v,ww = (QForm f) . vv,ww by Th49
.= 0. K by A5 ; :: thesis: verum
end;
hence x in leftker (LQForm (RQForm f)) by A5; :: thesis: verum
end;
thus leftker (LQForm (RQForm f)) c= leftker (QForm f) :: thesis: rightker (QForm f) = rightker (LQForm (RQForm f))
proof
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in leftker (LQForm (RQForm f)) or x in leftker (QForm f) )
assume x in leftker (LQForm (RQForm f)) ; :: thesis: x in leftker (QForm f)
then consider vv being Vector of (VectQuot V,(LKer (RQForm f))) such that
A6: ( x = vv & ( for ww being Vector of (VectQuot W,(RKer f)) holds (LQForm (RQForm f)) . vv,ww = 0. K ) ) ;
reconsider v = vv as Vector of (VectQuot V,(LKer f)) by Th48;
now
let ww be Vector of (VectQuot W,(RKer f)); :: thesis: (QForm f) . v,ww = 0. K
thus (QForm f) . v,ww = (LQForm (RQForm f)) . vv,ww by Th49
.= 0. K by A6 ; :: thesis: verum
end;
hence x in leftker (QForm f) by A6; :: thesis: verum
end;
thus rightker (QForm f) c= rightker (LQForm (RQForm f)) :: according to XBOOLE_0:def 10 :: thesis: rightker (LQForm (RQForm f)) c= rightker (QForm f)
proof
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in rightker (QForm f) or x in rightker (LQForm (RQForm f)) )
assume x in rightker (QForm f) ; :: thesis: x in rightker (LQForm (RQForm f))
then consider ww being Vector of (VectQuot W,(RKer f)) such that
A7: ( x = ww & ( for vv being Vector of (VectQuot V,(LKer f)) holds (QForm f) . vv,ww = 0. K ) ) ;
now
let vv be Vector of (VectQuot V,(LKer (RQForm f))); :: thesis: (LQForm (RQForm f)) . vv,ww = 0. K
reconsider v = vv as Vector of (VectQuot V,(LKer f)) by Th48;
thus (LQForm (RQForm f)) . vv,ww = (QForm f) . v,ww by Th49
.= 0. K by A7 ; :: thesis: verum
end;
hence x in rightker (LQForm (RQForm f)) by A7; :: thesis: verum
end;
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in rightker (LQForm (RQForm f)) or x in rightker (QForm f) )
assume x in rightker (LQForm (RQForm f)) ; :: thesis: x in rightker (QForm f)
then consider ww being Vector of (VectQuot W,(RKer f)) such that
A8: ( x = ww & ( for vv being Vector of (VectQuot V,(LKer (RQForm f))) holds (LQForm (RQForm f)) . vv,ww = 0. K ) ) ;
now
let vv be Vector of (VectQuot V,(LKer f)); :: thesis: (QForm f) . vv,ww = 0. K
reconsider v = vv as Vector of (VectQuot V,(LKer (RQForm f))) by Th48;
thus (QForm f) . vv,ww = (LQForm (RQForm f)) . v,ww by Th49
.= 0. K by A8 ; :: thesis: verum
end;
hence x in rightker (QForm f) by A8; :: thesis: verum