Read Complete Works of Lewis Carroll Online
Authors: Lewis Carroll
There is no Conclusion.
10.
All
x
are
m
;
All
y
′
are
m
′
.
∴
All
x
are
y
;
All
y
′
are
x
′
.
11.
No
m
are
x
;
All
y
′
are
m
′
.
There is no Conclusion.
12.
No
x
are
m
;
All
y
are
m
.
∴
All
y
are
x
′
.
SL5-A
Solutions for § 5, Nos.
1
–12.
1.
I have been out for a walk;
I am feeling better.
Univ.
is “persons”;
m
= the Class of I’s;
x
= persons who have been out for a walk;
y
= persons who are feeling better.
All
m
are
x
;
All
m
are
y
.
∴
Some
x
are
y
.
i.e.
Somebody, who has been out for a walk, is feeling better.
2.
No one has read the letter but John;
No one, who has
not
read it, knows what it is about.
Univ.
is “persons”;
m
= persons who have read the letter;
x
= the Class of Johns;
y
= persons who know what the letter is about.
No
x
′
are
m
;
No
m
′
are
y
.
∴
No
x
′
are
y
.
i.e.
No one, but John, knows what the letter is about.
3.
Those who are not old like walking;
You and I are young.
Univ.
is “persons”;
m
= old;
x
= persons who like walking;
y
= you and I.
All
m
′
are
x
;
All
y
are
m
′
.