I’m reading the book An Introduction to Mathematical Logic: To Truth
Through Proof by Peter B. Andrews. He says (p 52) that a first order
logic wff A is a substitution instance of a tautology iff there is a
propositional calculus tautology B such that A has the form

  p1 … p(n)
S             B.
  C1 … C(n)

What does this mean? Is p(i) a propositional variable and C(i) a
first order logic wff?

–

Henry Choy
c…@cs.usask.ca

What do we explore now, Spock?
How about the wild sorority girls of the planet Playtex?