A.2. Logical forms

Forms for which there is symbolic notation

Symbolic notation English notation or English reading
Negation ¬ φ not φ
Conjunction φ ∧ ψ both φ and ψ and ψ)
Disjunction φ ∨ ψ either φ or ψ or ψ)
The conditional φ → ψ
ψ ← φ
if φ then ψ
yes ψ if φ
implies ψ)
if φ)
Predication θτ1...τn θ fits τ1, ..., ’n τn
Identity τ = υ τ is υ
Compound term γτ1...τn γ of τ1, ..., ’n τn
Predicate abstract λx φ the property of x that φ
Complex functor λx τ the function of x yielding τ
Universal quantification ∀x θx forall x θx
everything, x, is such that θx
Restricted universal (∀x: ρx) θx forall x st ρx θx
everything, x, such that ρx is such that θx
Existential quantification ∃x θx forsome x θx
something, x, is such that θx
Restricted existential (∃x: ρx) θx forsome x st ρx θx
something, x, such that ρx is such that θx
Definite description Ix ρx the x st ρx
the thing, x, such that ρx

Some paraphrases of other forms

Truth-functional compounds
neither φ nor ψ ¬ (φ ∨ ψ)
¬ φ ∧ ¬ ψ
ψ only if φ ¬ ψ ← ¬ φ
ψ unless φ ψ ← ¬ φ
Generalizations
All Cs are such that ( ... they ... ) (∀x: x is a C) ... x ...
No Cs are such that ( ... they ... ) (∀x: x is a C) ¬ ... x ...
Only Cs are such that ( ... they ... ) (∀x: ¬ x is a C) ¬ ... x ...
with: among Bs add to the restriction: x is a B
except Es ¬ x is an E
other than τ ¬ x = τ
Numerical quantifier phrases
At least 1 C is such that ( ... it ... ) (∃x: x is a C) ... x ...
At least 2 Cs are such that ( ... they ... ) (∃x: x is a C) (∃y: y is a C ∧ ¬ y = x) ( ... x ... ∧ ... y ... )
Exactly 1 C is such that ( ... it ... ) (∃x: x is a C) ( ... x ... ∧ (∀y: y is a C ∧ ¬ y = x) ¬  ... y ... )
or
(∃x: x is a C) ( ... x ... ∧ (∀y: y is a C ∧ ... y ... ) x = y)
Definite descriptions (on Russell’s analysis)
The C is such that ( ... it ... ) (∃x: x is a C ∧ (∀y: ¬ y = x) ¬ y is a C) ... x ...
or
(∃x: x is a C ∧ (∀y: y is a C) x = y) ... x ...
Glen Helman 01 Aug 2004