4.1.xa. Exercise answers

1. a.

Tommy ate his vegetablesTommy didn’t get any dessert

Tommy ate his vegetables ∨ ¬ Tommy got dessert

V ∨ ¬ D
either V or not D

[D: Tommy got dessert; V: Tommy ate his vegetables]
  b.

¬ (Mike heard either the phone or the doorbell)

¬ (Mike heard the phoneMike heard the doorbell)

¬ (P ∨ D)
not either P or D

[D: Mike heard the doorbell; P: Mike heard the phone]
  c.

Mike wasn’t homeMike wasn’t answering the phone

¬ Mike was home ∨ ¬ Mike was answering the phone

¬ H ∨ ¬ P
either not H or not P

[H: Mike was home; P: Mike was answering the phone]
  d.

The package was senteither the package is still on its way or it’s been lost in the mail

The package was sent ∧ (the package is still on its waythe package has been lost in the mail)

S ∧ (W ∨ L)
both S and either W or L

[L: the package has been lost in the mail; S: the package was sent; W: the package is still on its way]
  e.

Neither the House nor the Senate had acted on the billthe White House expressed confidence that the bill would pass

¬ either the House or the Senate had acted on the billthe White House expressed confidence that the bill would pass

¬ (the House had acted on the billthe Senate had acted on the bill) ∧ the White House expressed confidence that the bill would pass

¬ (H ∨ S) ∧ W
both not either H or S and W

[H: the House had acted on the bill; S: the Senate had acted on the bill; W: the White House expressed confidence that the bill would pass]
  f.

¬ Sam will pass through without either stopping by or calling

¬ (Sam will pass through ∧ ¬ Sam will either stop by or call)

¬ (Sam will pass through ∧ ¬ (Sam will stop bySam will call))

¬ (P ∧ ¬ (S ∨ C))
not both P and not either S or C

[C: Sam will call; P: Sam will pass through; S: Sam will stop by]
  g.

Davis will take you or give you directionsEdwards will take you or give you directions

(Davis will take youDavis will give you directions) ∨ (Edwards will take youEdwards will give you directions)

(D ∨ G) ∨ (E ∨ V)
either either D or G or either E or V

[D: Davis will take you; E: Edwards will take you; G: Davis will give you directions; V: Edwards will give you directions]
  h.

We’ll have a can without an openerwe’ll have an opener without a can

(we’ll have a canwe won’t have an opener) ∨ (we’ll have an openerwe won’t have a can)

(we’ll have a can ∧ ¬ we’ll have an opener) ∨ (we’ll have an opener ∧ ¬ we’ll have a can)

(C ∧ ¬ O) ∨ (O ∧ ¬ C)
either both C and not O or both O and not C

[C: we’ll have a can; O: we’ll have an opener]
  i.

¬ either Jan or Ken had matches or a lighter

¬ (Jan had matches or a lighterKen had matches or a lighter)

¬ ((Jan had matchesJan had a lighter) ∨ (Ken had matchesKen had a lighter))

¬ ((M ∨ L) ∨ (K ∨ G))
not either either M or L or either K or G

[G: Ken had a lighter; K: Ken had matches; L: Jan had a lighter; M: Jan had matches]
  j.

Both Ann and Bill were in townneither Ann nor Bill knew the other was in town

(Ann was in townBill was in town) ∧ ¬ either Ann or Bill knew the other was in town

(Ann was in townBill was in town) ∧ ¬ (Ann knew Bill was in townBill knew Ann was in town)

(A ∧ B) ∧ ¬ (K ∨ N)
both both A and B and not either K or N

[A: Ann was in town; B: Bill was in town; K: Ann knew Bill was in town; N: Bill knew Ann was in town]
  k.

Tom will handle both the scheduling and the publicityDick will handle both the scheduling and the publicityHarry will handle both the scheduling and the publicity

(Tom will handle the schedulingTom will handle the publicity) ∨ (Dick will handle the schedulingDick will handle the publicity) ∨ (Harry will handle the schedulingHarry will handle the publicity)

(T ∧ P) ∨ (D ∧ B) ∨ (H ∧ L)
(both T and S) or (both D and C) or (both T and S)

[B: Dick will handle the publicity; D: Dick will handle the scheduling; H: Harry will handle the scheduling; L: Harry will handle the publicity; P: Tom will handle the publicity; T: Tom will handle the scheduling]
Note: this sentence is ambiguous and could also be interpreted as equivalent to the following one.
  l.

The scheduling will be handled by either Tom, Dick, or Harrythe publicity will be handled by either Tom, Dick, or Harry

(the scheduling will be handled by Tomthe scheduling will be handled by Dickthe scheduling will be handled by Harry) ∧ (the publicity will be handled by Tomthe publicity will be handled by Dickthe publicity will be handled by Harry)

(T ∨ D ∨ H) ∧ (P ∨ B ∨ L)
both (T or D or H) and (P or B or L)

[B: the publicity will be handled by Dick; D: the scheduling will be handled by Dick; H: the scheduling will be handled by Harry; L: the publicity will be handled by Harry; P: the publicity will be handled by Tom; T: the scheduling will be handled by Tom]
2. a.
both A and either B or C
 
  b.
either both A and B or C
 
  c.
¬ ( A ∨ ¬ B )
 
 
  d.
( A ∨ B ) ∧ ( A ∨ C )
 
3. a.

It was the butlerit was the nephew

It was either the butler or the nephew

  b.

¬ (the alarm workedthe sprinkler worked)

¬ (either the alarm or the sprinkler worked)

Neither the alarm nor the sprinkler worked

  c.

¬ the part arrived ¬ the part was the problem

The part didn’t arrivethe part wasn’t the problem

Either the part didn’t arrive or it wasn’t the problem

  d.

Ann has a large car ¬ (Bill will ride with usCarol will ride with us)

Ann has a large car ∨ ¬ Bill and Carol will ride with us

Ann has a large carBill and Carol won’t both ride with us

Either Ann has a large car or Bill and Carol won’t both ride with us

Note: both is introduced here to help distinguish this sentence from A ∨ (¬ B ∧ ¬ C)
  e.

(it rained over nightthere was a heavy dew) ∧ it is wet

It rained over night or there was a heavy dewit is wet

It rained over night or there was a heavy dew but, either way, it is wet

Note: either way here serves to indicate that the scope of the disjunction has ended and that the final clause is unhedged and but reinforces this by marking the contrast between the indefinite disjunction and the definite final clause.
  f.

(AAA ∧ Co. will profit from the dealZZZ Inc. will profit from the deal) ∨ (the deal will fall through ∧ ¬ (AAA ∧ Co. will profit from the dealZZZ Inc. will profit from the deal))

AAA ∧ Co. and ZZZ Inc. will both profit from the deal ∨ (the deal will fall through ∧ ¬ (either AAA ∧ Co. or ZZZ Inc. will profit from the deal))

AAA ∧ Co. and ZZZ Inc. will both profit from the deal ∨ (the deal will fall throughneither AAA ∧ Co. nor ZZZ Inc. will profit from the deal)

AAA ∧ Co. and ZZZ Inc. will both profit from the dealthe deal will fall through and neither AAA ∧ Co. nor ZZZ Inc. will profit from it)

Either AAA ∧ Co. and ZZZ Inc. will both profit from the deal, or the deal will fall through and neither will profit from it

Glen Helman 25 Sep 2004