let R be good Ring; :: thesis: for T being InsType of (SCM R) st T = 4 holds
JumpParts T = {{}}
let T be InsType of (SCM R); :: thesis: ( T = 4 implies JumpParts T = {{}} )
assume A1: T = 4 ; :: thesis: JumpParts T = {{}}

hereby :: according to TARSKI:def 3,XBOOLE_0:def 10 :: thesis: {{}} c= JumpParts T

let x be set ; :: thesis: ( x in JumpParts T implies x in {{}} )
assume x in JumpParts T ; :: thesis: x in {{}}
then consider I being Instruction of (SCM R) such that
W1: x = JumpPart I and
W2: InsCode I = T ;
consider a, b being Data-Location of R such that
W3: I = MultBy (a,b) by A1, W2, Th20;
x = {} by W1, W3, RECDEF_2:def 2;
hence x in {{}} by TARSKI:def 1; :: thesis: verum

end;

set a = the Data-Location of R;
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in {{}} or x in JumpParts T )
assume x in {{}} ; :: thesis: x in JumpParts T
then x = {} by TARSKI:def 1;
then X: x = JumpPart (MultBy ( the Data-Location of R, the Data-Location of R)) by RECDEF_2:def 2;
InsCode (MultBy ( the Data-Location of R, the Data-Location of R)) = 4 by RECDEF_2:def 1;
hence x in JumpParts T by X, A1; :: thesis: verum