# eliminate product terms in equation [duplicate]

I would like to eliminate all terms that contain the product of dxy, dwz, and dxz, i.e. the final result should read as dxy +b dwz+ c dxz. Thanks in advance for any hint.

a dxy +b dwz+ c dxz+e dxy dwz +f dxy dxz +g dwz dxz + h dxy dxz dwz

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• @user58765 Can you check the post that Carl cited and say if it helps to solve your problem? Jun 13 '18 at 22:00

expr = a dxy +b dwz+ c dxz+e dxy dwz +f dxy dxz +g dwz dxz + h dxy dxz dwz;

Normal @ Series[
expr /. v:(dxy|dwz|dxz) -> v t,
{t, 0, 1}
] /. t->1


b dwz + a dxy + c dxz

Or this way

expr = a dxy + b dwz + c dxz + e dxy dwz + f dxy dxz + g dwz dxz +
h dxy dxz dwz // Expand;

prodterms = Apply[Times, Subsets[{dxy, dwz, dxz}, {2, 3}], 2]

(*   {dwz dxy, dxy dxz, dwz dxz, dwz dxy dxz}   *)