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Full Idea
I introduce the sign |- to mean 'we may validly conclude'. To call it the 'assertion sign' is misleading. It may conveniently be read as 'therefore'.
Gist of Idea
The sign |- may be read as 'therefore'
Source
E.J. Lemmon (Beginning Logic [1965], 1.2)
Book Ref
Lemmon,E.J.: 'Beginning Logic' [Nelson 1979], p.11
A Reaction
[Actually no gap between the vertical and horizontal strokes of the sign] As well as meaning 'assertion', it may also mean 'it is a theorem that' (with no proof shown).
22435 | The logician's '→' does not mean the English if-then [Quine] |
9512 | We write the 'negation' of P (not-P) as ¬ [Lemmon] |
9508 | The sign |- may be read as 'therefore' [Lemmon] |
9511 | We write the conditional 'if P (antecedent) then Q (consequent)' as P→Q [Lemmon] |
9510 | That proposition that either P or Q is their 'disjunction', written P∨Q [Lemmon] |
9509 | That proposition that both P and Q is their 'conjunction', written P∧Q [Lemmon] |
9513 | We write 'P if and only if Q' as P↔Q; it is also P iff Q, or (P→Q)∧(Q→P) [Lemmon] |
9514 | If A and B are 'interderivable' from one another we may write A -||- B [Lemmon] |
12005 | The symbol 'ι' forms definite descriptions; (ιx)F(x) says 'the x which is such that F(x)' [Forbes,G] |
7799 | Proposition logic has definitions for its three operators: or, and, and identical [Girle] |