:: Predicate Calculus for Boolean Valued Functions, II
:: by Shunichi Kobayashi and Yatsuka Nakamura
::
:: Received March 13, 1999
:: Copyright (c) 1999-2021 Association of Mizar Users
theorem
:: BVFUNC_4:1
for
Y
being non
empty
set
for
a
,
b
,
c
being
Function
of
Y
,
BOOLEAN
st
a
'<'
b
'imp'
c
holds
a
'&'
b
'<'
c
proof
end;
theorem
:: BVFUNC_4:2
for
Y
being non
empty
set
for
a
,
b
,
c
being
Function
of
Y
,
BOOLEAN
st
a
'&'
b
'<'
c
holds
a
'<'
b
'imp'
c
proof
end;
theorem
:: BVFUNC_4:3
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
holds
a
'or'
(
a
'&'
b
)
=
a
proof
end;
theorem
:: BVFUNC_4:4
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
holds
a
'&'
(
a
'or'
b
)
=
a
proof
end;
theorem
Th5
:
:: BVFUNC_4:5
for
Y
being non
empty
set
for
a
being
Function
of
Y
,
BOOLEAN
holds
a
'&'
(
'not'
a
)
=
O_el
Y
proof
end;
theorem
:: BVFUNC_4:6
for
Y
being non
empty
set
for
a
being
Function
of
Y
,
BOOLEAN
holds
a
'or'
(
'not'
a
)
=
I_el
Y
proof
end;
theorem
Th7
:
:: BVFUNC_4:7
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
holds
a
'eqv'
b
=
(
a
'imp'
b
)
'&'
(
b
'imp'
a
)
proof
end;
theorem
Th8
:
:: BVFUNC_4:8
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
holds
a
'imp'
b
=
(
'not'
a
)
'or'
b
proof
end;
theorem
:: BVFUNC_4:9
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
holds
a
'xor'
b
=
(
(
'not'
a
)
'&'
b
)
'or'
(
a
'&'
(
'not'
b
)
)
proof
end;
theorem
Th10
:
:: BVFUNC_4:10
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
holds
(
a
'eqv'
b
=
I_el
Y
iff (
a
'imp'
b
=
I_el
Y
&
b
'imp'
a
=
I_el
Y
) )
proof
end;
theorem
:: BVFUNC_4:11
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
st
a
'eqv'
b
=
I_el
Y
holds
(
'not'
a
)
'eqv'
(
'not'
b
)
=
I_el
Y
proof
end;
theorem
:: BVFUNC_4:12
for
Y
being non
empty
set
for
a
,
b
,
c
,
d
being
Function
of
Y
,
BOOLEAN
st
a
'eqv'
b
=
I_el
Y
&
c
'eqv'
d
=
I_el
Y
holds
(
a
'&'
c
)
'eqv'
(
b
'&'
d
)
=
I_el
Y
proof
end;
theorem
:: BVFUNC_4:13
for
Y
being non
empty
set
for
a
,
b
,
c
,
d
being
Function
of
Y
,
BOOLEAN
st
a
'eqv'
b
=
I_el
Y
&
c
'eqv'
d
=
I_el
Y
holds
(
a
'imp'
c
)
'eqv'
(
b
'imp'
d
)
=
I_el
Y
proof
end;
theorem
:: BVFUNC_4:14
for
Y
being non
empty
set
for
a
,
b
,
c
,
d
being
Function
of
Y
,
BOOLEAN
st
a
'eqv'
b
=
I_el
Y
&
c
'eqv'
d
=
I_el
Y
holds
(
a
'or'
c
)
'eqv'
(
b
'or'
d
)
=
I_el
Y
proof
end;
theorem
:: BVFUNC_4:15
for
Y
being non
empty
set
for
a
,
b
,
c
,
d
being
Function
of
Y
,
BOOLEAN
st
a
'eqv'
b
=
I_el
Y
&
c
'eqv'
d
=
I_el
Y
holds
(
a
'eqv'
c
)
'eqv'
(
b
'eqv'
d
)
=
I_el
Y
proof
end;
::Chap. 2 Predicate Calculus
theorem
:: BVFUNC_4:16
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
holds
All
(
(
a
'eqv'
b
)
,
PA
,
G
)
=
(
All
(
(
a
'imp'
b
)
,
PA
,
G
)
)
'&'
(
All
(
(
b
'imp'
a
)
,
PA
,
G
)
)
proof
end;
theorem
:: BVFUNC_4:17
for
Y
being non
empty
set
for
a
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
,
PB
being
a_partition
of
Y
holds
All
(
a
,
PA
,
G
)
'<'
Ex
(
a
,
PB
,
G
)
proof
end;
theorem
:: BVFUNC_4:18
for
Y
being non
empty
set
for
a
,
u
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
st
a
'imp'
u
=
I_el
Y
holds
(
All
(
a
,
PA
,
G
)
)
'imp'
u
=
I_el
Y
proof
end;
theorem
:: BVFUNC_4:19
for
Y
being non
empty
set
for
u
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
st
u
is_independent_of
PA
,
G
holds
Ex
(
u
,
PA
,
G
)
'<'
u
proof
end;
theorem
:: BVFUNC_4:20
for
Y
being non
empty
set
for
u
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
st
u
is_independent_of
PA
,
G
holds
u
'<'
All
(
u
,
PA
,
G
)
proof
end;
theorem
:: BVFUNC_4:21
for
Y
being non
empty
set
for
u
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
,
PB
being
a_partition
of
Y
st
u
is_independent_of
PB
,
G
holds
All
(
u
,
PA
,
G
)
'<'
All
(
u
,
PB
,
G
)
proof
end;
theorem
:: BVFUNC_4:22
for
Y
being non
empty
set
for
u
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
,
PB
being
a_partition
of
Y
st
u
is_independent_of
PA
,
G
holds
Ex
(
u
,
PA
,
G
)
'<'
Ex
(
u
,
PB
,
G
)
proof
end;
theorem
:: BVFUNC_4:23
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
holds
All
(
(
a
'eqv'
b
)
,
PA
,
G
)
'<'
(
All
(
a
,
PA
,
G
)
)
'eqv'
(
All
(
b
,
PA
,
G
)
)
proof
end;
theorem
:: BVFUNC_4:24
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
holds
All
(
(
a
'&'
b
)
,
PA
,
G
)
'<'
a
'&'
(
All
(
b
,
PA
,
G
)
)
proof
end;
theorem
:: BVFUNC_4:25
for
Y
being non
empty
set
for
a
,
u
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
holds
(
All
(
a
,
PA
,
G
)
)
'imp'
u
'<'
Ex
(
(
a
'imp'
u
)
,
PA
,
G
)
proof
end;
theorem
:: BVFUNC_4:26
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
st
a
'eqv'
b
=
I_el
Y
holds
(
All
(
a
,
PA
,
G
)
)
'eqv'
(
All
(
b
,
PA
,
G
)
)
=
I_el
Y
proof
end;
theorem
:: BVFUNC_4:27
for
Y
being non
empty
set
for
a
,
b
being
Function
of
Y
,
BOOLEAN
for
G
being
Subset
of
(
PARTITIONS
Y
)
for
PA
being
a_partition
of
Y
st
a
'eqv'
b
=
I_el
Y
holds
(
Ex
(
a
,
PA
,
G
)
)
'eqv'
(
Ex
(
b
,
PA
,
G
)
)
=
I_el
Y
proof
end;