  Generally accepted scheme distinguishes two main classes of supernovae (SNe):
Ia resulting from the old stellar population (deflagration of a white dwarf in
close binary systems), and SNe of type II and Ib/c whose ancestors are young
massive stars (died in a core-collapse explosion). Concerning the latter, there
are suggestions that the SNe II are connected to early B stars, and SNe Ib/c to
isolated O or Wolf-Rayet (W-R) stars. However, little or no effort was made to
further separate SNe Ib from Ic. We have used assumed SN rates for different SN
types in spiral galaxies in an attempt to perform this task. If isolated
progenitor hypothesis is correct, our analysis indicates that SNe Ib result
from stars of main-sequence mass $23 \mathcal{M}_{\odot} \lesssim \mathcal{M}
\lesssim 30 \mathcal{M}_{\odot}$, while the progenitors of SNe Ic are more
massive stars with $\mathcal{M} \gtrsim 30 \mathcal{M}_{\odot}$.
  Alternatively, if the majority of SNe Ib/c appear in close binary systems
(CBs) then they would result from the same progenitor population as most of the
SNe II, i.e. early B stars with initial masses of order $\mathcal{M} \sim 10
\mathcal{M}_{\odot}$. Future observations of SNe at high-redshift ($z$) and
their rate will provide us with unique information on SN progenitors and
star-formation history of galaxies. At higher-$z$ (deeper in the cosmic past)
we expect to see the lack of type Ia events, i.e. the dominance of
core-collapse SNe. Better understanding of the stripped-envelope SNe (Ib/c),
and their potential use as distance indicators at high-$z$, would therefore be
of great practical importance.
