let R be non degenerated Ring; for X being non empty set
for z being Element of X holds Support (iota (z,R)) = {z}
let X be non empty set ; for z being Element of X holds Support (iota (z,R)) = {z}
let z be Element of X; Support (iota (z,R)) = {z}
thus
Support (iota (z,R)) c= {z}
XBOOLE_0:def 10 {z} c= Support (iota (z,R))
let o be object ; TARSKI:def 3 ( not o in {z} or o in Support (iota (z,R)) )
assume A7:
o in {z}
; o in Support (iota (z,R))
then A8:
o = z
by TARSKI:def 1;
A9:
dom (iota (z,R)) = X
by FUNCT_2:def 1;
(iota (z,R)) . o = 1. R
by A8, Def17;
then
(iota (z,R)) . o <> 0. R
;
hence
o in Support (iota (z,R))
by A7, A9, POLYNOM1:def 3; verum