Deduction substituting both sides of an implication, with \( \varphi \) and \( x \) disjoint. See also sbimd. (Contributed by Wolf Lammen, 6-May-2023.) Revise [df-sb]. (Revised by Steven Nguyen, 6-Jul-2023.)
Deduction substituting both sides of an implication, with \( \varphi \) and \( x \) disjoint. See also sbimd. (Contributed by Wolf Lammen, 6-May-2023.) Revise [df-sb]. (Revised by Steven Nguyen, 6-Jul-2023.)