1 Penn Frontotemporal Degeneration Center, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA 2 Department of Linguistics, University of ...

存在量词 ``∃`` （ ``\ex`` ）用于表示短语“存在” 。Lean 中的形式表达式 ``∃ x : ℝ, 2 < x ∧ x < 3`` 是说存在一个介于2到3之间的实数。（我们将在 :numref:`conjunction_and_biimplication` 探讨合取符号。

% of TeX increases, you will probably want to edit this, but % it should be fine as is for beginners. \emph{H\"artig's quantifier} is a quantifier which takes two ...