==== <math>(\forall x_1)(\forall x_2)R(x_1,x_2) \vdash (\forall x_2)(\forall x_1)R(x_1,x_2)</math> ====
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==== <math>(\forall x) \varphi varphi_1 \land \psi varphi_2 \dashv\vdash (\forall x) \varphi varphi_1 \land (\forall x)\psivarphi_2</math> ====
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