Question Number 167189 by rexford last updated on 09/Mar/22
Commented by MJS_new last updated on 09/Mar/22
$${a}<{b}\wedge{c}<{d}\:\Rightarrow\:\left({a}+{c}\right)<\left({b}+{d}\right) \\ $$$${x}<{y}\wedge−{x}<−{y}\:\Rightarrow\:\left({x}−{x}\right)<\left({y}−{y}\right)\:\Rightarrow\:\mathrm{0}<\mathrm{0}\:\mathrm{false} \\ $$