let L be lower-bounded continuous LATTICE; :: thesis: for V being upper Open Subset of L
for N being non empty countable Subset of L
for x, y being Element of L st V "/\" N c= V & y in V & not x in V holds
ex p being irreducible Element of L st
( x <= p & not p in uparrow ({y} "/\" N) )

let V be upper Open Subset of L; :: thesis: for N being non empty countable Subset of L
for x, y being Element of L st V "/\" N c= V & y in V & not x in V holds
ex p being irreducible Element of L st
( x <= p & not p in uparrow ({y} "/\" N) )

let N be non empty countable Subset of L; :: thesis: for x, y being Element of L st V "/\" N c= V & y in V & not x in V holds
ex p being irreducible Element of L st
( x <= p & not p in uparrow ({y} "/\" N) )

let x, y be Element of L; :: thesis: ( V "/\" N c= V & y in V & not x in V implies ex p being irreducible Element of L st
( x <= p & not p in uparrow ({y} "/\" N) ) )

assume that
A1: ( V "/\" N c= V & y in V ) and
A2: not x in V ; :: thesis: ex p being irreducible Element of L st
( x <= p & not p in uparrow ({y} "/\" N) )

consider O being Open Filter of L such that
A3: {y} "/\" N c= O and
A4: O c= V and
y in O by ;
( uparrow O c= O & O c= uparrow O ) by ;
then uparrow O = O ;
then A5: uparrow ({y} "/\" N) c= O by ;
not x in O by A2, A4;
then x in O ` by XBOOLE_0:def 5;
then consider p being Element of L such that
A6: x <= p and
A7: p is_maximal_in O ` by WAYBEL_6:9;
reconsider p = p as irreducible Element of L by ;
take p ; :: thesis: ( x <= p & not p in uparrow ({y} "/\" N) )
thus x <= p by A6; :: thesis: not p in uparrow ({y} "/\" N)
p in O ` by ;
hence not p in uparrow ({y} "/\" N) by ; :: thesis: verum