let C1, C2 be Coherence_Space; :: thesis: union (LinCoh (C1,C2)) = [:(union C1),(union C2):]
thus union (LinCoh (C1,C2)) c= [:(union C1),(union C2):] :: according to XBOOLE_0:def 10 :: thesis: [:(union C1),(union C2):] c= union (LinCoh (C1,C2))

proof

let x be object ; :: according to TARSKI:def 3 :: thesis: ( not x in union (LinCoh (C1,C2)) or x in [:(union C1),(union C2):] )
assume x in union (LinCoh (C1,C2)) ; :: thesis: x in [:(union C1),(union C2):]
then consider a being set such that
A1: x in a and
A2: a in LinCoh (C1,C2) by TARSKI:def 4;
ex f being U-linear Function of C1,C2 st a = LinTrace f by A2, Def20;
hence x in [:(union C1),(union C2):] by A1; :: thesis: verum

end;

let x, y be object ; :: according to RELAT_1:def 3 :: thesis: ( not [x,y] in [:(union C1),(union C2):] or [x,y] in union (LinCoh (C1,C2)) )
assume A3: [x,y] in [:(union C1),(union C2):] ; :: thesis: [x,y] in union (LinCoh (C1,C2))
then A4: y in union C2 by ZFMISC_1:87;
x in union C1 by A3, ZFMISC_1:87;
then ex f being U-linear Function of C1,C2 st LinTrace f = {[x,y]} by A4, Th59;
then ( [x,y] in {[x,y]} & {[x,y]} in LinCoh (C1,C2) ) by Def20, TARSKI:def 1;
hence [x,y] in union (LinCoh (C1,C2)) by TARSKI:def 4; :: thesis: verum