The next step was taken by Évariste Galois in 1832, although his work remained unpublished until 1846, when he considered for the first time what is now called the closure property of a group of permutations, which he expressed as if in such a group one has the substitutions S and T then one has the substitution ST.
O paso seguinte deuno Évariste Galois en 1832 (se ben o seu traballo permaneceu sen publicar ata o 1846), cando considerou por vez primeira o que hoxe chamaríamos propiedade de clausura dun grupo de permutacións, que el expresou como ... se nun grupo deste tipo téñense as substitucións S e T, entón tamén se ten a substitución ST.