let L be non empty transitive RelStr ; for S being non empty meet-closed Subset of L
for x, y being Element of S st ex_inf_of {x,y},L holds
( ex_inf_of {x,y}, subrelstr S & "/\" ({x,y},(subrelstr S)) = "/\" ({x,y},L) )
let S be non empty meet-closed Subset of L; for x, y being Element of S st ex_inf_of {x,y},L holds
( ex_inf_of {x,y}, subrelstr S & "/\" ({x,y},(subrelstr S)) = "/\" ({x,y},L) )
let x, y be Element of S; ( ex_inf_of {x,y},L implies ( ex_inf_of {x,y}, subrelstr S & "/\" ({x,y},(subrelstr S)) = "/\" ({x,y},L) ) )
A1:
x is Element of (subrelstr S)
by YELLOW_0:def 15;
A2:
y is Element of (subrelstr S)
by YELLOW_0:def 15;
assume A3:
ex_inf_of {x,y},L
; ( ex_inf_of {x,y}, subrelstr S & "/\" ({x,y},(subrelstr S)) = "/\" ({x,y},L) )
subrelstr S is non empty full meet-inheriting SubRelStr of L
by Def1;
then
"/\" ({x,y},L) in the carrier of (subrelstr S)
by A1, A2, A3, YELLOW_0:def 16;
hence
( ex_inf_of {x,y}, subrelstr S & "/\" ({x,y},(subrelstr S)) = "/\" ({x,y},L) )
by A1, A2, A3, YELLOW_0:65; verum