| Description: An inference version of
the transitive laws for implication imim2 14 and
imim1 15, which Russell and Whitehead call "the
principle of the
syllogism...because...the syllogism in Barbara is derived from
them"
(quote after Theorem *2.06 of [WhiteheadRussell] p. 101). Some authors
call this law a "hypothetical syllogism."
(A bit of trivia: this is the most commonly referenced assertion in our
database. In second place is ax-mp 7, followed by visset 1804, bitr 173,
imp 350, and ex 373. The Metamath program command 'show
usage' shows the
number of references.) |