Theorem ferio 2566

Description: "Ferio" ("Ferioque"), one of the syllogisms of Aristotelian logic. No ph is ps, and some ch is ph, therefore some ch is not ps. (In Aristotelian notation, EIO-1: MeP and SiM therefore SoP.) For example, given "No homework is fun" and "Some reading is homework", therefore "Some reading is not fun". This is essentially a logical axiom in Aristotelian logic. Example from https://en.wikipedia.org/wiki/Syllogism. (Contributed by David A. Wheeler, 24-Aug-2016.) (Revised by David A. Wheeler, 2-Sep-2016.)

Hypotheses

Ref	Expression
ferio.maj	|- A. x ( ph -> -. ps )
ferio.min	|- E. x ( ch /\ ph )

Assertion

Ref	Expression
ferio	|- E. x ( ch /\ -. ps )

Proof of Theorem ferio

Step	Hyp	Ref	Expression
1		ferio.maj	. 2 |- A. x ( ph -> -. ps )
2		ferio.min	. 2 |- E. x ( ch /\ ph )
3	1, 2	darii 2565	1 |- E. x ( ch /\ -. ps )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 384   A.wal 1481   E.wex 1704

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-12 2047

This theorem depends on definitions:  df-bi 197  df-an 386  df-ex 1705

This theorem is referenced by: (None)