There are two “reasonable” limit operations in convergent- divergent proof of Harmonious Series:
1+1/2 +1/3+1/4+...+1/n +... (1)
=1+1/2 +(1/3+1/4 )+(1/5+1/6+1/7+1/8)+... (2)
>1+ 1/2 +( 1/4+1/4 )+(1/8+1/8+1/8+1/8)+... (3)
=1+ 1/2 + 1/2 + 1/2 + 1/2 + ...------>infinity (4)
(1) During the whole process in dealing with infinite substances (infinitesimals) in limit calculations, no one dare to say “let them be zero or get the limit”. So, the infinitesimals in the calculating operations would never be too small to be out of the calculations and the calculations dealing with infinitesimals would be carried our forever. This situation has been existing in mathematics since antiquity------ those items of Un--->0 never be 0 all the time and Harmonious Series is divergent, so we can produce infinite numbers bigger than 1/2 or 1 or 100 or 100000 or 10000000000 or… from infinite Un--->0 items in Harmonious Series and change an infinitely decreasing Harmonious Series with the property of Un--->0 into any infinite constant series with the property of Un--->constant or any infinitely increasing series with the property of Un--->infinity. Here, with limit theory and technique, we see a “strict mathematically proven” modern version of ancient Zeno’s Paradox.
(2) During the process in dealing with infinite substances (infinitesimals) in limit calculations, someone suddenly cries “let them be zero or get the limit”. So, all in a sudden the infinitesimals in the calculations become too small to stay inside the calculations, they should disappear from (be out of) any limit calculation formulas immediately. This situation has been existing in mathematics since antiquity-------those items of Un--->0 must be 0 from some time and Harmonious Series is not divergent, so we cannot produce infinite numbers bigger than 1/2 or 1 or 100 or 100000 or 10000000000 or…from infinite Un--->0 items in Harmonious Series. But if it is convergent, another paradox appears.
But when and to which should or should not people treat infinitesimals appearing in infinite numeral cognitions that way?
Does limit theory need basic theory, what is it?