let Y be non empty set ; :: thesis: for a being Element of Funcs Y,BOOLEAN
for G being Subset of (PARTITIONS Y)
for A, B being a_partition of Y st G is independent holds
'not' (All (All a,A,G),B,G) = Ex (Ex ('not' a),B,G),A,G
let a be Element of Funcs Y,BOOLEAN ; :: thesis: for G being Subset of (PARTITIONS Y)
for A, B being a_partition of Y st G is independent holds
'not' (All (All a,A,G),B,G) = Ex (Ex ('not' a),B,G),A,G
let G be Subset of (PARTITIONS Y); :: thesis: for A, B being a_partition of Y st G is independent holds
'not' (All (All a,A,G),B,G) = Ex (Ex ('not' a),B,G),A,G
let A, B be a_partition of Y; :: thesis: ( G is independent implies 'not' (All (All a,A,G),B,G) = Ex (Ex ('not' a),B,G),A,G )
A1: Ex ('not' a),B,G = 'not' (All a,B,G) by BVFUNC_2:20;
assume G is independent ; :: thesis: 'not' (All (All a,A,G),B,G) = Ex (Ex ('not' a),B,G),A,G
hence 'not' (All (All a,A,G),B,G) = Ex (Ex ('not' a),B,G),A,G by A1, Th17; :: thesis: verum