let s, t be non empty finite set ; ( card s = 23 & card t = 365 implies prob (not-one-to-one s,t) > 1 / 2 )
assume Z0:
card s = 23
; ( not card t = 365 or prob (not-one-to-one s,t) > 1 / 2 )
assume Z1:
card t = 365
; prob (not-one-to-one s,t) > 1 / 2
set E = not-one-to-one s,t;
set comega = card (Funcs s,t);
(2 * (card (not-one-to-one s,t))) / 2 > (card (Funcs s,t)) / 2
by XREAL_1:76, Th9, Z0, Z1;
then
(card (not-one-to-one s,t)) / (card (Funcs s,t)) > ((card (Funcs s,t)) / 2) / (card (Funcs s,t))
by XREAL_1:76;
then
(card (not-one-to-one s,t)) / (card (Funcs s,t)) > ((card (Funcs s,t)) / (card (Funcs s,t))) / 2
;
then
(card (not-one-to-one s,t)) / (card (Funcs s,t)) > 1 / 2
by XCMPLX_0:def 7;
hence
prob (not-one-to-one s,t) > 1 / 2
by RPR_1:def 4; verum