Update /math (2)

apps/web/src/routes/(main)/math/+page.svelte

@@ -264,6 +264,8 @@ const talks: Talk[] = [
       <section>
         <h3>論文・発表等</h3>
 
+        <p>上から新しい順に並んでいます。</p>
+
         <h4 class="text-primary font-bold">論文</h4>
 
         <ol class="space-y-3">
@@ -276,6 +278,7 @@ const talks: Talk[] = [
           {/each}
         </ol>
 
+        {#if papers.some((p) => !isAccepted(p))}
           <h4 class="text-primary font-bold">プレプリント</h4>
 
           <ol class="space-y-3">
@@ -287,6 +290,7 @@ const talks: Talk[] = [
               {/if}
             {/each}
           </ol>
+        {/if}
 
         <h4 class="text-primary font-bold">口頭発表</h4>