How to solve
E_(x_(28))
Let
\beta
be the collection of Circular regions (interiors of circles) and
\beta ^(')
be the Collection of rectangular regions (interiors of rectangles) in the plane, with sides para
(%)/()
l to
x
-axis. (i) Prove that
\beta
is a basis for a topology
\tau _(\beta )
on the plane. (ii) Prove that
\beta ^(')
is a basis for a topology
\tau _(B^('))
on the plane. (iii) Prove that
\tau _(B)
and
\tau _(B^('))
coincide
(\tau _(B)
)
=
(
\tau _(B^(')))
. # #
E_(E_(xg))
Let
S
be the Collection of all straight lines in the plane which are parallel to the
x
-axis. If
S
is a subbasis for a topology
\tau _(on )R^(2)
, describe all open sets in
(R^(2),\tau )
. Ex
x_(3)
Answer the same question as in Exas where
S
is now the collection of all circles in the plane. Ex31 Answer the same questionasin
E_(x29)
when
S
is the Collection of all circles in the plane which have their centres on the
x
-axis.