Does refraction increase or decrease the apparent diameters of the Sun and Moon near the horizon?

Yes, due to the noticeable difference in refraction for the lower and upper edges of the disk of the Sun and Moon, their diameters appear to be shortened in the vertical direction.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.