Is it permissible to use the plus sign (+) in mathematics even though it resembles the cross?

The plus sign (+) in mathematics is not exactly like the cross. The cross, to Christians, refers to a crucified human and consists of two intersecting beams, one vertical and the other horizontal. The upper part of the vertical beam might be shorter than the lower part, or its ends might be level. Even if we assume a resemblance, the purpose of the sign is a specific mathematical function, and therefore, there is no impediment to its use.