1. Vertical vs Horizontal Justice
When speaking of a just distribution of income or wealth, one has to differentiate between various levels, i.e between vertical and horizontal justice. More important in its real-world effects is vertical justice, which, for ex, can compare two individuals with different incomes but otherwise absolutely equal prerequisites.  A common view of justice holds that someone with higher income should pay higher taxes than someone who only has a low income.
Horizontal justice is, however, all too often forgotten. Here one could, for ex, compare two famimies each with a household income of 100000€ per year, and who differ only in the fact that the one family has one child, the other two children. Applying vertical justice, one would not support tax advantages for the second family because in relation to others it belongs to the “better off”. In the context of horizontal justice this approach cannot be justified because the second family is disadvantaged Vis-à-vis the first on account of its higher needs, and because children are especially protected under the German constitution in the case of Germany. It should be clear that the conclusions would be similar if one considered a large family with an annual income of one million German Marks, where the majority would see the payment of child benefit as unjust. Yet this reaction would not fulfil the criterion of horizontal justice in the context of which the millionaire with two children would have to be compared with a millionare with one child.
It has become clear that we will not achieve the ideal of comprehensive justice. Nonetheless considerations are appropriate on the issue of how one can come closer to this goal. A possibility of at least taking children more into account could be achieved via an indirect right to vote for children where the parents - more precisely: the legal guardians - each have half a vote per child. (where there is only one legal guardian, they would obviously have a full vote). Even if parents were often to vote differently than their children wish, this procedure can nevertheless be justified by the fact that parents also take on the rights and duties of their children in other areas of life. The share of the vote would increase by more than 20% in Germany, which would lead to parties that are orientated towards the median voter, who in german cities is single, having to take the younger generation more into account. Or in the case of Brexit, as older generation had more votes for leaving, let’s assume this time one person does not necessarily counts as one vote but according to their age, the vote of one person will count as 1 vote minus the percentage of the age multiple 1 vote = the offical counted vote => taking the younger generation’s vote more into account.
One can conclude that in any case the subjects of justice to be taken into account for the organisation of justice should be clearly defined.
2. Equality of Sacrifice  
When sacrifices are to be born, then from a justice perspective, these sacrifices should be the same for those involved. It is, however, by no means obvious what one should understand by equal sacrifice.
Assume A has an income of 3000 € per month, B has an income of 6000€ per month. Then the sacrifice is absolutely equal if both individuals, for ex, have to pay a tax of 1000€ each. This perspective though is open to criticism because one can argue that A has to pay more tax in percentage terms than B, although B is richer than A. If one applies the concept of relative equality of sacrifice, B would have to pay 2000€ in taxes, A still only 1000€, as in this case the percentage share is the same, namely one third.
The concepts of absolute and relative equality of opportunity are closely related to the Pareto criterion, according to which a measure should only be carried out if no one is worse off than before. This criterion is, however, only applicable when one takes absolute equality of  sacrifice as the reference basis: even if no one is absolutely worse off, and only one person is better off, then the relative position of the majority of economic subjects has worsened because in relation to the individual who is absolutely better off, their position is worse.