Is this move legal in predicate logic ( quantifying universally over a variable about which one has no information)
65682
Why does universal generalization work? (the rule of inference)
12186
How does predicate logic handle contradictory statements about something that does not exist?
71670
Predicates and Quantifiers?
86248
Is $\exists x(x=a)$ a valid formula in first order logic with equality?
158295
First Order Logic clauses decidability
72034
Truth table and the meaning of $\oplus$ in propositional logic
36721
Is "The empty set is a subset of any set" a convention?
14849
Decidability of a predicate.
36498
Is logical "or" exclusive or inclusive in prime ideal definition
147947
Does double negation distribute over implication intuitionistically?
77736
Quantifier Order Matters?
27107
intersection of the empty set and vacuous truth
27506
What does it mean for a variable to be free for something?
67490
Restricing domains for universal and existential quantifiers
109423
Purpose of universal property of a product.
83963
Proving knowledge of a preimage of a hash without disclosing it?
42590
Understanding implication in logic truth tables (excerpt from textbook)